1.
The change in position of an object is known as its _______.
Explanation
Displacement refers to the change in position of an object, usually measured in a straight line from the starting point to the ending point. It takes into account both the distance and direction of the movement. Displacement is a vector quantity, meaning it has both magnitude and direction. It is different from distance, which only refers to the total length of the path traveled by an object.
2.
An object's _______ can be calculated by dividing its displacement by the time.
Explanation
The displacement of an object refers to the change in its position, while time measures the duration of this change. By dividing the displacement by the time, we can determine the object's velocity. Velocity is a vector quantity that describes both the speed and direction of an object's motion. Therefore, it is the appropriate term to use in this context when calculating an object's displacement relative to the time taken.
3.
______ is calculated by dividing distance by time.
Explanation
Speed is a measure that is calculated by dividing the distance traveled by an object by the time taken to cover that distance. It represents how fast an object is moving and is typically measured in units such as meters per second or kilometers per hour. Speed is a fundamental concept in physics and is used to describe the rate at which an object changes its position.
4.
A runner runs seven times around a track. If the track is 0.25 miles long, the distance he has run is _______ miles.
Explanation
The runner runs seven times around a track, and each lap is 0.25 miles long. To find the total distance, we multiply the number of laps (7) by the distance per lap (0.25 miles). This gives us 7 * 0.25 = 1.75 miles.
5.
A runner runs seven times around a track. If the track is 0.25 miles long, his displacement is ________ miles.
Explanation
The runner starts and ends at the same point, so his displacement is zero. Displacement measures the change in position from the starting point to the ending point, and since he returns to the starting point after running seven laps, his displacement is zero.
6.
A runner runs seven times around a track. If the track is 0.25 miles long and it took him 18 minutes to run the seven laps, his average speed is ________ mph.
Explanation
The average speed of the runner can be calculated by dividing the total distance covered by the time taken. In this case, the runner ran a total distance of 7 laps, each lap being 0.25 miles long, which gives a total distance of 1.75 miles. The time taken to run this distance is 18 minutes. Dividing the distance by the time gives us an average speed of 1.75 miles/18 minutes. Converting the time to hours (18 minutes = 0.3 hours), we get a speed of 1.75 miles/0.3 hours, which simplifies to 5.8 mph.
7.
A runner runs seven times around a track. If the track is 0.25 miles long and it took him 18 minutes to run the seven laps, his average velocity is ________ mph.
Explanation
The runner's average velocity is 0 mph because velocity is defined as the displacement divided by the time taken. In this case, the runner starts and ends at the same point, so the displacement is 0. Since the time taken is 18 minutes, the average velocity is 0 mph.
8.
Displacement is considered a _______ quantity.
Explanation
Displacement is considered a vector quantity because it has both magnitude and direction. In physics, vectors are used to represent physical quantities that require both of these properties to be fully described. Displacement, which refers to the change in position of an object, can be measured in terms of distance and direction from the initial position. Therefore, it falls under the category of vector quantities.
9.
Kathy's dog breaks free from its leash and she has to chase it all over the neighborhood. At first, she runs 3.0 blocks east. Then she turns and runs 5.0 blocks west. Finally, she runs another 1.5 blocks east. Kathy ran a distance of ______ blocks.
Explanation
The question describes Kathy's movements in terms of blocks. She first runs 3.0 blocks east, then turns and runs 5.0 blocks west, and finally runs another 1.5 blocks east. To find the total distance she ran, we add up the distances traveled in each direction: 3.0 + 5.0 + 1.5 = 9.5 blocks. Therefore, Kathy ran a distance of 9.5 blocks.
10.
Kathy's dog breaks free from its leash and she has to chase it all over the neighborhood. At first, she runs 3.0 blocks east. Then she turns and runs 5.0 blocks west. Finally, she runs another 1.5 blocks east. Kathy's displacement is _______.
Explanation
Kathy initially runs 3.0 blocks east, then changes direction and runs 5.0 blocks west. This means she has moved 3.0 - 5.0 = -2.0 blocks to the west. Finally, she runs another 1.5 blocks east. Adding this to her previous displacement, she has moved -2.0 + 1.5 = -0.5 blocks to the west. Therefore, Kathy's displacement is 0.5 blocks west. The option -0.5 blocks east is incorrect as it suggests that Kathy has moved to the east, which is not the case.
11.
The term for how quickly an object's velocity changes is known as __________.
Explanation
Acceleration is the term used to describe how quickly an object's velocity changes. It measures the rate at which an object's speed or direction changes over time. When an object accelerates, it means that it is either speeding up, slowing down, or changing its direction of motion. Therefore, acceleration is the correct term to describe the rate of change in velocity.
12.
Which of the following statements describes a situation in which the car is undergoing an acceleration?
Correct Answer(s)
A. A car slows down as it approaches a red light.
B. A car speeds up as the light turns green.
C. A car makes a right hand turn at a constant speed.
Explanation
A car slows down as it approaches a red light and a car speeds up as the light turns green both describe situations in which the car is undergoing an acceleration. In both cases, the car's velocity is changing, either decreasing or increasing, which indicates acceleration. A car making a right-hand turn at a constant speed does not involve any change in velocity, so it does not describe a situation of acceleration.
13.
On a distance versus time graph, a straight horizontal line indicates which of the following?
Correct Answer
C. The object is not moving.
Explanation
A straight horizontal line on a distance versus time graph indicates that the object is not moving. This is because the distance covered by the object remains constant over time, indicating that there is no change in position. If the object were maintaining a constant speed, the graph would show a straight diagonal line, not a horizontal line. Similarly, if the object were accelerating, the graph would show a curved line, not a straight line.
14.
On a velocity versus time graph, a straight horizontal line indicates which of the following?
Correct Answer
A. The object is maintaining a constant speed.
Explanation
A straight horizontal line on a velocity versus time graph indicates that the object is maintaining a constant speed. This is because the slope of a velocity versus time graph represents acceleration, and a horizontal line has a slope of zero, indicating no acceleration. Therefore, the object is not changing its speed and is moving at a constant rate.
15.
Based on the graph below, which statement correctly describes the object's motion?
Correct Answer
C. The object is maintaining a constant speed.
Explanation
The graph shows a straight horizontal line, indicating that the object's position does not change over time. Since the position is constant, the object is maintaining a constant speed.
16.
Based on the graph below, which statement correctly describes the object's motion?
Correct Answer
A. The object is speeding up.
Explanation
Based on the graph, we can see that the object's velocity is increasing over time. This indicates that the object is accelerating, which means it is speeding up. Therefore, the correct statement is that the object is speeding up.
17.
Forces that cancel each other out are called ______ forces
Correct Answer
B. Balanced
Explanation
Forces that cancel each other out are called balanced forces. This means that the forces acting on an object are equal in magnitude and opposite in direction, resulting in no net force on the object. When forces are balanced, the object remains in a state of equilibrium, with no change in its motion.
18.
A ball is thrown straight up in the air. According to Newton's first law of motion, what is the reason for the ball falling back to Earth?
Correct Answer
A. A force has acted on it.
Explanation
According to Newton's first law of motion, an object at rest will remain at rest, and an object in motion will continue in motion with the same speed and in the same direction unless acted upon by an external force. In the case of the ball thrown straight up in the air, the force of gravity acts on it, causing it to accelerate downwards and eventually fall back to Earth. Therefore, the reason for the ball falling back to Earth is that a force (gravity) has acted on it.
19.
When unbalanced forces act on an object,
Correct Answer
A. The object accelerates
Explanation
When unbalanced forces act on an object, the object accelerates. This means that the object's velocity changes, either by increasing or decreasing. Acceleration occurs when there is a net force acting on the object that is not balanced by an equal and opposite force. In this case, the unbalanced forces cause a change in the object's motion, resulting in acceleration.
20.
A 10. N force is applied to a given mass which causes it to accelerate at 1.0 m/s/s. If the same force is applied to an object with half the mass, what would the acceleration be?
Correct Answer
B. 2.0 m/s/s
Explanation
When the same force is applied to an object with half the mass, the acceleration will be twice as much. This is because according to Newton's second law of motion, the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. Therefore, if the force remains constant but the mass is halved, the resulting acceleration will be doubled. In this case, since the original acceleration was 1.0 m/s/s, when the force is applied to an object with half the mass, the acceleration will be 2.0 m/s/s.
21.
A 30 kg child exerts a force of 100 N on a 50 kg object. The force the object exerts on the child is
Correct Answer
C. 100 N
Explanation
According to Newton's third law of motion, for every action, there is an equal and opposite reaction. In this case, the child exerts a force of 100 N on the object. Therefore, the object will exert an equal and opposite force of 100 N on the child.
22.
If the net force applied to an object is doubled, the acceleration of the object is
Correct Answer
B. Doubled
Explanation
When the net force applied to an object is doubled, according to Newton's second law of motion, the acceleration of the object will also double. This is because there is a direct relationship between the net force and acceleration. As the force increases, the acceleration also increases proportionally. Therefore, if the net force is doubled, the acceleration of the object will also double.
23.
A car whose mass is 2000 kg is accelerated from rest to a speed of 15 m/s in 10. s on a level highway. What is the net force?
Correct Answer
B. 3000 N
Explanation
The net force can be calculated using Newton's second law, which states that force is equal to mass multiplied by acceleration. In this case, the mass of the car is given as 2000 kg and the acceleration can be determined using the formula: acceleration = (final velocity - initial velocity) / time. Plugging in the values, we get: acceleration = (15 m/s - 0 m/s) / 10 s = 1.5 m/s^2. Now, we can calculate the net force: force = mass * acceleration = 2000 kg * 1.5 m/s^2 = 3000 N.
24.
The wooden block must be
Correct Answer
D. Accelerating to the right
Explanation
The wooden block must be accelerating to the right because acceleration is the rate of change of velocity. Since the block is accelerating, it means there is a change in its velocity, and since the block is moving to the right, the change in velocity is also in the rightward direction. Therefore, the correct answer is accelerating to the right.
25.
If F1 equals 2 N and F2 equals 5 N, then the net force on the block is
Correct Answer
D. 3 N right
Explanation
The net force on the block is determined by adding up the individual forces acting on it. In this case, F1 is 2 N to the left and F2 is 5 N to the right. Since the forces are acting in opposite directions, we subtract the smaller force from the larger force to find the net force. 5 N - 2 N equals 3 N. Since the larger force is to the right, the net force on the block is 3 N to the right.
26.
_____ describes how fast something is going, whereas, ______ describes how fast something is going and in a certain direction.
Correct Answer
D. Speed, velocity
Explanation
Speed is a measure of how fast something is going, while velocity not only describes the speed but also includes the direction in which the object is moving. Therefore, speed only focuses on the magnitude of the movement, while velocity takes into account both the magnitude and direction.