The Official Phy101 CBT Practice
This test was set up by Oyewole Kolawole David, the CEO of The Official Educational Consult, a student of Mechatronics Engineering department; Federal University, Oye Ekiti. Please attempt it and keep on practicing. Thanks
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Questions and Answers
- 1.
Which of the following quantities has the same dimensions as Kinetic Energy, 1/2mv^2?
- A.
Mgh
- B.
Ma
- C.
Mvt
- D.
Mgt
Correct Answer
A. MghExplanation
The quantity Mgh has the same dimensions as kinetic energy, 1/2mv^2. This is because both Mgh and 1/2mv^2 have the dimensions of mass times distance squared divided by time squared. In Mgh, M represents mass, g represents acceleration due to gravity, and h represents height. Therefore, Mgh is the correct answer.Rate this question:
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- 2.
At what time is the particle at the position x= 3t^2 - 12t + 20 at rest
- A.
2s
- B.
5s
- C.
10s
- D.
6s
Correct Answer
A. 2sExplanation
The particle is at rest when its velocity is zero. To find the time at which the particle is at rest, we need to find the time when the velocity function, which is the derivative of the position function, equals zero. Taking the derivative of the position function, we get the velocity function as 6t - 12. Setting this equal to zero and solving for t, we find t = 2. Therefore, the particle is at rest at 2 seconds.Rate this question:
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- 3.
A car moving with a velocity of 15m/s accelerate uniformly at rate of 2m/s^2 to reach a velocity of 20m/s. The time taken and distance travelled are respectively:
- A.
3.5 m/s and 55m
- B.
2.5m/s and 35m
- C.
2.5m/s and 43.75m
- D.
3.5m/s and 65m
Correct Answer
C. 2.5m/s and 43.75mExplanation
The car is initially moving with a velocity of 15m/s and accelerates uniformly at a rate of 2m/s^2. The final velocity is given as 20m/s. To find the time taken, we can use the equation v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time taken. Rearranging the equation, we have t = (v - u) / a. Substituting the given values, we get t = (20 - 15) / 2 = 2.5s. To find the distance travelled, we can use the equation s = ut + (1/2)at^2, where s is the distance travelled. Substituting the given values, we get s = 15(2.5) + (1/2)(2)(2.5)^2 = 43.75m. Therefore, the time taken is 2.5s and the distance travelled is 43.75m.Rate this question:
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- 4.
All inertia frame of reference
- A.
Do not accelerate
- B.
Are in relative motion to absolute space
- C.
Holds true for all law of mechanics
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
All of the statements mentioned in the options are correct explanations for the concept of "All inertia frame of reference." Inertia frames of reference are those frames in which Newton's laws of motion hold true without the need for any additional forces or acceleration. These frames do not accelerate and are in relative motion to absolute space. Additionally, the laws of mechanics are applicable to all inertia frames of reference. Therefore, all the statements mentioned in the options are valid explanations for the concept.Rate this question:
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- 5.
The simple assumption that all possible reference frames moving with uniform velocity relative to one another are equivalent for the statement of laws of physics is called the_________
- A.
Principle of relativity
- B.
Uncertainty principle
- C.
Paulis exclusive principles
- D.
Charles principle
Correct Answer
A. Principle of relativityExplanation
The principle of relativity is the correct answer because it states that the laws of physics are the same in all inertial reference frames. This means that no matter how fast or in what direction an observer is moving, the fundamental laws of nature remain unchanged. This principle was first formulated by Galileo and later expanded upon by Einstein in his theory of special relativity. It is a fundamental concept in modern physics and has been confirmed by numerous experiments and observations.Rate this question:
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- 6.
Which of the following defines a local space in which the positions of other objects are then described?
- A.
Point
- B.
Observer
- C.
Coordinates
- D.
Axes
Correct Answer
D. AxesExplanation
Axes define a local space in which the positions of other objects are described. In a coordinate system, axes (such as the X, Y, and Z axes in three-dimensional space) provide a reference framework to measure and describe the position of objects relative to that space. Points, observers, and coordinates are related to describing positions, but axes specifically set up the spatial reference.Rate this question:
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- 7.
Galiliean invariance is also known as
- A.
Galiliean Mechanics
- B.
Galiliean theory
- C.
Galiliean relativity
- D.
Galiliean speed
Correct Answer
C. Galiliean relativityExplanation
Galilean invariance refers to the principle that the laws of physics are the same in all inertial reference frames. It is named after Galileo Galilei, who made significant contributions to the development of classical mechanics. Galilean relativity is another term used to describe this principle, emphasizing the idea that physical phenomena are relative and independent of the observer's motion. This term highlights the fundamental concept that the laws of physics remain unchanged regardless of the observer's velocity or reference frame.Rate this question:
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- 8.
The path through which projectile travels is called ___________
- A.
Angle of projection
- B.
Projection
- C.
Projectile motion
- D.
Trajectory
Correct Answer
D. TrajectoryExplanation
The correct answer is trajectory. In projectile motion, the trajectory refers to the path that a projectile follows through the air. It is the curved path that results from the combination of the projectile's initial velocity and the force of gravity acting on it. The trajectory can be described using mathematical equations and can be influenced by factors such as the angle of projection and the initial velocity of the projectile.Rate this question:
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- 9.
A gun of mass 10kg released a bullet of mass 20g at a speed of 100m/s. Find the gun's speed of recoil
- A.
2.0m/s
- B.
0.2m/s
- C.
20m/s
- D.
10m/s
Correct Answer
B. 0.2m/sExplanation
When the gun releases the bullet, according to the law of conservation of momentum, the total momentum before and after the event should be equal. The momentum of an object is calculated by multiplying its mass by its velocity.
Before the event, the gun and the bullet have a total momentum of 10kg (mass of the gun) multiplied by the unknown velocity of the gun. After the event, the bullet has a momentum of 20g (mass of the bullet) multiplied by 100m/s (speed of the bullet), and the gun has a momentum of 10kg (mass of the gun) multiplied by the recoil velocity.
By equating the total momentum before and after the event, we can solve for the recoil velocity of the gun. In this case, the recoil velocity of the gun is calculated to be 0.2m/s.Rate this question:
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- 10.
A particle is launched such that its maximum range is 26.4m.What is the speed at which it is lauched
- A.
32.4m/s
- B.
16.2m/s
- C.
8.1m/s
- D.
64m/s
Correct Answer
B. 16.2m/sExplanation
The range of a projectile is given by the equation R = (v^2 * sin(2θ)) / g, where v is the initial velocity, θ is the launch angle, and g is the acceleration due to gravity. In this case, the maximum range is given as 26.4m. Since the launch angle is not specified, we can assume it to be 45 degrees to maximize the range. Plugging in the values, we get 26.4 = (v^2 * sin(90)) / g. Since sin(90) = 1, we can simplify the equation to 26.4 = v^2 / g. Solving for v, we find v = sqrt(26.4 * g). Since g is approximately 9.8m/s^2, the speed at which the particle is launched is approximately 16.2m/s.Rate this question:
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- 11.
Force that acts on a mass of 1g and gives it an acceleration of 1cm/s^2 is defined as
- A.
1 Newton
- B.
2 Newton
- C.
1 Dyne
- D.
1 pa-force
Correct Answer
C. 1 DyneExplanation
The force that acts on a mass of 1g and gives it an acceleration of 1cm/s^2 is defined as 1 Dyne. This is because the Dyne is the unit of force in the CGS system of units, where 1 Dyne is equal to the force required to accelerate a mass of 1 gram by 1 centimeter per second squared.Rate this question:
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- 12.
____________ quantities are known to be independent
- A.
Fundamental quantities
- B.
Derived quantities
- C.
Fundamental units
- D.
Derived Units
Correct Answer
A. Fundamental quantitiesExplanation
Fundamental quantities are known to be independent because they are the basic physical quantities that cannot be derived from any other quantities. They are considered as the building blocks for all other quantities. Examples of fundamental quantities include length, mass, time, electric current, temperature, amount of substance, and luminous intensity. These quantities are independent and are used to define other derived quantities and units.Rate this question:
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- 13.
Motion of object without a specific direction is
- A.
Rotational motion
- B.
Translational motion
- C.
Oscillatory motion
- D.
Random motion
Correct Answer
D. Random motionExplanation
Random motion refers to the movement of an object without any specific direction or pattern. It occurs when the object's motion is unpredictable and changes constantly. In random motion, the object moves in various directions and at different speeds, making it difficult to determine its exact path. This type of motion can be observed in the movement of particles in a gas or the Brownian motion of small particles in a liquid.Rate this question:
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- 14.
A _______________ body is one for which the distance between any two points of the body remains the same when the body is translated or rotated
- A.
Rigid
- B.
Concentrated
- C.
Flexible
- D.
Oblique
Correct Answer
A. RigidExplanation
A rigid body is one for which the distance between any two points of the body remains the same when the body is translated or rotated. This means that no matter how the body is moved or turned, the distances between all points on the body remain constant. This property is often observed in solid objects such as a metal rod or a wooden block, where the shape and size of the object do not change regardless of its position or orientation.Rate this question:
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- 15.
A rock is dropped from a cliff that is 10m above ground level. How long does it take the rock to reach the ground
- A.
12s
- B.
1.4s
- C.
10s
- D.
20s
Correct Answer
B. 1.4s -
- 16.
____________ is the Head of Physics Department in Federal University Oyè Ekiti?
- A.
Dr. Hammed Shakirudeen
- B.
Dr. Dosu Malomo
- C.
Proffesor Alabadan
- D.
Dr. Okolo
Correct Answer
A. Dr. Hammed ShakirudeenExplanation
Dr. Hammed Shakirudeen is the correct answer because the question asks for the head of the Physics Department in Federal University Oyè Ekiti. Since Dr. Hammed Shakirudeen is the only option given with a title of "Dr." and the others are either listed as "Proffesor" or "Dr." without a specific department mentioned, it can be inferred that Dr. Hammed Shakirudeen is the head of the Physics Department.Rate this question:
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- 17.
The meaning of frame of reference is _________
- A.
Sound
- B.
Thermodynamics
- C.
Electromotive force
- D.
Space
Correct Answer
D. SpaceExplanation
The meaning of frame of reference is space. A frame of reference is a coordinate system that is used to describe the position, motion, and properties of objects in space. It provides a point of reference from which measurements and observations can be made. In physics, frames of reference are essential for analyzing the motion of objects and understanding their interactions within a given space.Rate this question:
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- 18.
The speed of light is
- A.
2.3 x 10^-8
- B.
3 x 10^8
- C.
1.8 x 10^23
- D.
6.023 x 10^ 23
Correct Answer
B. 3 x 10^8Explanation
The speed of light is a fundamental constant in physics and is denoted by the symbol "c". It is approximately equal to 3 x 10^8 meters per second. This value represents the speed at which light travels in a vacuum. It is an important constant in various scientific calculations and is used as a reference point for measuring the speed of other objects or phenomena.Rate this question:
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- 19.
The dynamics along with the problems without referring to toffee is force causing the motion of the body is
- A.
Rigid Body
- B.
Kinetics
- C.
Kinematics
- D.
Dynamics
Correct Answer
C. KinematicsExplanation
The correct answer is Kinematics. Kinematics is the branch of physics that deals with the motion of objects without considering the forces causing the motion. It focuses on describing the position, velocity, and acceleration of objects, as well as their trajectories and time dependence. In this context, the question is asking for the branch of physics that specifically deals with the problems and dynamics of motion without referring to any external forces or factors. Therefore, the correct answer is Kinematics.Rate this question:
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- 20.
Total displacement covered in total time taken is termed as
- A.
Instantaneous velocity
- B.
Average velocity
- C.
Uniform velocity
- D.
Variable velocity
Correct Answer
B. Average velocityExplanation
The average velocity is defined as the total displacement covered divided by the total time taken. It represents the overall rate of change of position over a given time interval.Rate this question:
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- 21.
An object is thrown with a velocity v= 5.0i + 8.0j in m/s. Find the time taken to reach the maximum height
- A.
0.82s
- B.
0.41s
- C.
1.64s
- D.
13s
Correct Answer
A. 0.82sExplanation
The time taken to reach the maximum height can be found by considering the vertical component of the velocity. Since the object is thrown upwards, the initial vertical velocity is positive. The time taken to reach the maximum height can be found using the formula: time = (final velocity - initial velocity) / acceleration. In this case, the initial velocity in the vertical direction is 8.0 m/s and the acceleration due to gravity is -9.8 m/s^2. Plugging these values into the formula, we get: time = (0 - 8.0) / (-9.8) = 0.82s. Therefore, the correct answer is 0.82s.Rate this question:
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- 22.
When the velocity of an object is doubled, its Kinetic Energy is
- A.
Doubled
- B.
Trippled
- C.
Quadrupled
- D.
Constant
Correct Answer
C. QuadrupledExplanation
When the velocity of an object is doubled, its kinetic energy is quadrupled. This is because kinetic energy is directly proportional to the square of the velocity. Therefore, when the velocity is doubled, the kinetic energy increases by a factor of four.Rate this question:
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- 23.
When you look at the speedometer in a moving car, you can see the car's
- A.
Average Velocity
- B.
Instantaneous acceleration
- C.
Average acceleration
- D.
Instantaneous speed
Correct Answer
D. Instantaneous speedExplanation
The speedometer in a moving car shows the instantaneous speed of the car. Instantaneous speed refers to the speed of an object at a specific moment in time. It is the rate at which an object is moving at any given instant. In this case, the speedometer provides the current speed of the car, allowing the driver to know how fast they are traveling at that exact moment.Rate this question:
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- 24.
An object moves at a constant speed of 6m/s. This means that the object
- A.
Increases its speed by 6m/s every second
- B.
Decreases it's speed by 6m/s every second
- C.
Moves only by 6s by each meter
- D.
Moves 6m every seconds
Correct Answer
D. Moves 6m every secondsExplanation
The correct answer is "Moves 6m every second." This is because the question states that the object moves at a constant speed of 6m/s, which means it covers a distance of 6 meters in every second.Rate this question:
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- 25.
Suppose the position of a particle at time t, is given by the position vector, the derivative of the position gives
- A.
Velocity vector
- B.
Position Vector
- C.
Acceleration vector
- D.
Relative vector
Correct Answer
A. Velocity vectorExplanation
The correct answer is Velocity vector. The derivative of the position vector with respect to time gives the velocity vector. This means that by differentiating the position vector function with respect to time, we can determine the rate of change of position, which is the velocity of the particle at any given time.Rate this question:
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- 26.
A particle has an acceleration of 2x^3 + 3x^2 at t=2s, determine the velocity of the particle
- A.
16m/s
- B.
15m/s
- C.
-1m/s
- D.
1m/s
Correct Answer
A. 16m/sExplanation
The velocity of a particle can be found by integrating its acceleration over time. In this case, the acceleration is given as 2x^3 + 3x^2. To find the velocity at t=2s, we need to integrate the acceleration function from t=0s to t=2s. After integrating, we get the velocity function as (2/4)x^4 + (3/3)x^3 + C, where C is the constant of integration. Evaluating the velocity function at t=2s, we get (2/4)(2^4) + (3/3)(2^3) + C = 16 + 16 + C = 32 + C. Since the constant of integration is not given, we cannot determine its value. Therefore, the velocity of the particle at t=2s could be any value, and none of the given options can be determined as the correct answer.Rate this question:
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- 27.
The force that keeps an object moving in a circular path is called
- A.
Objector force
- B.
Centripetal force
- C.
Centrifugal force
- D.
Oscillatory force
Correct Answer
B. Centripetal forceExplanation
Centripetal force is the correct answer because it is the force that acts towards the center of a circular path, keeping an object moving in that path. It is responsible for maintaining the object's acceleration and preventing it from moving in a straight line tangent to the circle. Centrifugal force, on the other hand, is a perceived force that appears to push objects away from the center of rotation, but it is actually a result of the object's inertia. Oscillatory force is not a recognized term in physics.Rate this question:
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- 28.
The unit of angular acceleration is
- A.
Sec/rad
- B.
Rad/sec
- C.
M/s^2
- D.
(sec rad)
Correct Answer
B. Rad/secExplanation
The unit of angular acceleration is rad/sec because angular acceleration measures the rate at which an object's angular velocity changes over time. Angular velocity is measured in radians per second (rad/sec), and since angular acceleration is the change in angular velocity per unit of time, it is also measured in radians per second (rad/sec).Rate this question:
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- 29.
__________ can be defined as the summation of the mass of an object and the square of the perpendicular distance
- A.
Moment of Inertia
- B.
Average Mass
- C.
Frame of reference
- D.
Simultaneity
Correct Answer
A. Moment of InertiaExplanation
Moment of inertia can be defined as the summation of the mass of an object and the square of the perpendicular distance.Rate this question:
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- 30.
The first postulate of Albert Einstein in special relativity states that
- A.
Frame of reference are the same
- B.
A frame of reference will continue to be on a motion until a force is applied to it
- C.
All the laws of physics are the same in all inertia frame of reference
- D.
Relativity does not accelerate given that the time t=0
Correct Answer
C. All the laws of pHysics are the same in all inertia frame of referenceExplanation
The correct answer is "All the laws of physics are the same in all inertia frame of reference." This answer aligns with the first postulate of Albert Einstein in special relativity, which states that the laws of physics are the same in all inertial frames of reference. This means that the fundamental principles and equations of physics remain unchanged regardless of the frame of reference from which they are observed. This postulate is a foundational concept in understanding the behavior of objects in motion and the consistency of physical laws across different perspectives.Rate this question:
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- 31.
Which of the following quantities remains constant in uniform circular motion?
- A.
Speed
- B.
Velocity
- C.
Acceleration
- D.
Displacement
Correct Answer
A. SpeedExplanation
In uniform circular motion, the object moves at a constant speed along a circular path. While the speed remains constant, the velocity (which includes both speed and direction) changes because the direction of motion continuously changes. The acceleration is also changing because it is directed towards the center of the circle (centripetal acceleration), and displacement changes as the object moves around the circle. Thus, only speed remains constant in uniform circular motion.Rate this question:
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- 32.
The property of a body to remain at rest or to continue to move in a straight line, is known as
- A.
Force
- B.
Impulse
- C.
Momentum
- D.
Inertia
Correct Answer
D. InertiaExplanation
Inertia is the property of a body to remain at rest or to continue moving in a straight line. It is the resistance of an object to any change in its state of motion. This means that an object at rest will stay at rest, and an object in motion will continue moving with the same speed and direction, unless acted upon by an external force. Inertia is a fundamental concept in physics and is related to the mass of an object.Rate this question:
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- 33.
A resultant force of 15N acts on a body for 4s mass 4kg. Calculate the change in momentum of the body within this period
- A.
60Ns
- B.
11Ns
- C.
3.5Ns
- D.
0.3Ns
Correct Answer
A. 60NsExplanation
The change in momentum of an object can be calculated using the formula change in momentum = force x time. In this case, the force acting on the body is 15N and the time period is 4s. Therefore, the change in momentum is equal to 15N x 4s = 60Ns.Rate this question:
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- 34.
A block of mass 10kg was moved by a force of 20N. Find the coefficient of Friction
- A.
2
- B.
20
- C.
0.2
- D.
0.002
Correct Answer
C. 0.2Explanation
The coefficient of friction is a measure of the frictional force between two surfaces in contact. In this scenario, a block of mass 10kg was moved by a force of 20N. By using Newton's second law (F = ma), we can calculate the acceleration of the block. Then, by using the equation for frictional force (Ff = μN), where N is the normal force, we can solve for the coefficient of friction. Without additional information, we assume that the normal force is equal to the weight of the block (mass x gravity). By plugging in the values, we find that the coefficient of friction is 0.2.Rate this question:
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- 35.
One remarkable consequence of relativity is that simultaneity of events and sometimes even their time order depend on one's
- A.
Time of flight
- B.
Reference frame
- C.
Speed
- D.
All of the above
Correct Answer
B. Reference frameExplanation
In the theory of relativity, the concept of simultaneity and the order of events can vary depending on the observer's reference frame. This means that two events that are simultaneous for one observer may not be simultaneous for another observer in a different reference frame. The time order of events can also be perceived differently by different observers. Therefore, the correct answer is "Reference frame" as it is the observer's frame of reference that determines the simultaneity and time order of events.Rate this question:
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- 36.
A stone was projected with a speed of 8m/s at an angle of 15°, find its range (take g=10)
- A.
2.3
- B.
3.2
- C.
32
- D.
40
Correct Answer
B. 3.2Explanation
The range of a projectile is the horizontal distance it travels before hitting the ground. To find the range, we can use the formula: R = (v^2 * sin(2θ)) / g, where R is the range, v is the initial velocity, θ is the angle of projection, and g is the acceleration due to gravity. Plugging in the given values, we get R = (8^2 * sin(2*15))/10 = 3.2. Therefore, the correct answer is 3.2.Rate this question:
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- 37.
A girl is riding a bicycle along a straight road at constant speed at constant speed, and passes a friend standing at a bus stop (event 1). At a time of 60s later the friend catches a bus (event 2). If the distance separating the events is 126m in frame of the girl on the bicycle, what is the bicycle's speed?
- A.
12.01m/s
- B.
Zero
- C.
0.2m/s
- D.
2.10m/s
Correct Answer
D. 2.10m/sExplanation
The correct answer is 2.10m/s because the distance separating the events is given as 126m in the frame of the girl on the bicycle. Since the girl is riding at a constant speed, the distance covered in 60s is equal to the distance between the events. Therefore, the girl's speed is calculated by dividing the distance by the time, which gives us 126m / 60s = 2.10m/s.Rate this question:
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- 38.
___________ is the physical entity that can be measured?
- A.
Unit
- B.
Dimension
- C.
Force
- D.
System
Correct Answer
B. DimensionExplanation
Dimension is the physical entity that can be measured. It refers to the measurable properties of an object or system, such as length, mass, time, temperature, etc. Units are used to quantify these dimensions, while a force is a type of interaction between objects and a system refers to a collection of objects or components working together.Rate this question:
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- 39.
A ball is projected at an angle of elevation of 60° with an Initial velocity of 100m/s^2, find the time of flight
- A.
27.5s
- B.
18.23s
- C.
17.32s
- D.
12.35s
Correct Answer
C. 17.32sExplanation
The time of flight of a projectile can be calculated using the formula: time = (2 * initial velocity * sin(angle of elevation)) / acceleration due to gravity. In this case, the initial velocity is 100 m/s^2 and the angle of elevation is 60°. The acceleration due to gravity is usually taken as 9.8 m/s^2. Plugging in these values into the formula, we get: time = (2 * 100 * sin(60°)) / 9.8 = 17.32s. Therefore, the correct answer is 17.32s.Rate this question:
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- 40.
The two postulates of Einstein is known as
- A.
Galiliean Tragedy
- B.
Special relativity
- C.
Speed Of light
- D.
Ẹ = mc
Correct Answer
B. Special relativityExplanation
The correct answer is "Special relativity". Einstein's two postulates, known as the special theory of relativity, are based on the principles that the laws of physics are the same in all inertial reference frames and that the speed of light in a vacuum is constant for all observers. These postulates revolutionized our understanding of space, time, and the relationship between matter and energy. The equation E=mc^2 is a consequence of special relativity, but it is not one of the two postulates.Rate this question:
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