1.
A slanted surface used to raise an object is ______________
Correct Answer
A. An inclined plane
Explanation
An inclined plane is a slanted surface that is used to raise an object. It allows for the object to be moved up or down with less force than if it were lifted straight up. This simple machine is commonly used in ramps, stairs, and even some playground equipment. It is an efficient way to move heavy objects or to reduce the amount of force needed to lift an object vertically. Therefore, the correct answer is an inclined plane.
2.
A device that does work with only one movement and changes the size and direction of a force is __________________
Correct Answer
B. A simple machine
Explanation
A simple machine is a device that can perform work with a single movement and can change the size and direction of a force. It is a basic mechanical device that helps to make work easier by multiplying or changing the direction of force. Examples of simple machines include levers, pulleys, inclined planes, screws, wheels and axles, and wedges. They are the building blocks of more complex machines and are used in various applications to reduce the amount of force required to perform tasks.
3.
A bar that is free to pivot about a fixed point is a _____________
Correct Answer
A. Lever
Explanation
A bar that is free to pivot about a fixed point is called a lever. A lever is a simple machine consisting of a rigid beam or bar that is able to rotate around a fixed point called the fulcrum. The lever allows for the amplification or redirection of force, making it a useful tool in many applications.
4.
The work output of a machine compared to the work input is the _________ of the machine.
Correct Answer
A. Efficiency
Explanation
Efficiency is a measure of how effectively a machine converts input work into output work. It is calculated by dividing the output work by the input work and multiplying by 100 to express it as a percentage. A higher efficiency value indicates that the machine is more effective in converting the input work into useful output work, while a lower efficiency value signifies that a significant amount of input work is wasted or converted into other forms of energy. Therefore, efficiency is the appropriate term to describe the work output of a machine compared to the work input.
5.
The amount by which a machine multiplies an effort force is called the _________
Correct Answer
D. Mechanical advantage
Explanation
The term "mechanical advantage" refers to the amount by which a machine can multiply an effort force. It is a measure of the effectiveness of a machine in reducing the amount of force required to perform a task. In other words, it quantifies the ratio between the output force produced by a machine and the input force applied to it. Therefore, "mechanical advantage" is the correct answer to the question.
6.
Two inclined planes put together form a simple machine called _________________
Correct Answer
B. A wedge
Explanation
When two inclined planes are put together, they form a simple machine called a wedge. A wedge is a triangular-shaped object with a sharp edge that is used to split, lift, or hold objects apart. It works by converting a force applied to its blunt end into a larger force exerted on its sharp end. This makes it easier to perform tasks such as cutting or splitting objects. Wedges are commonly used in tools like knives, axes, and chisels.
7.
An inclined plane wrapped around a cylindrical post is a
Correct Answer
A. Screw
Explanation
An inclined plane wrapped around a cylindrical post is known as a screw. This is because a screw is essentially an inclined plane in the form of a spiral wrapped around a cylinder. The inclined plane allows the screw to convert rotational motion into linear motion, making it useful for various applications such as fastening objects together or lifting heavy loads.
8.
Two or more simple machines working together is called ________________
Correct Answer
B. A compound machine
Explanation
A compound machine refers to two or more simple machines working together. In this case, the correct answer is "a compound machine" because it accurately describes the concept of multiple simple machines working in conjunction to perform a task.
9.
The unit for power is the ___________
Correct Answer
C. Watt
Explanation
The unit for power is the watt. Power is the rate at which work is done or energy is transferred or converted, and it is measured in watts. The watt is named after James Watt, a Scottish inventor who made significant contributions to the development of the steam engine. It is a derived unit in the International System of Units (SI), defined as one joule per second.
10.
A lever with a mechanical advantage greater than 1 is used to _____________
Correct Answer
C. Decrease effort force
Explanation
A lever with a mechanical advantage greater than 1 is used to decrease effort force. This means that the lever allows a smaller amount of force to be applied to move a larger load. By increasing the distance between the fulcrum and the point where the effort force is applied, the lever effectively multiplies the force applied, making it easier to move heavy objects.
11.
Three of the listed simple machines are basically the same. Choose the one that DOES NOT belong with the group.
Correct Answer
A. Wedge
Explanation
The wedge is the correct answer because it is the only simple machine that does not involve rotational motion. A wedge is used to separate or split objects by applying force in a pushing or pulling motion, while the lever, pulley, and wheel and axle all involve rotational motion to perform work.
12.
A system of pulleys designed to reduce the effort force is called _________________
Correct Answer
D. A block and tackle
Explanation
A block and tackle is a system of pulleys that is designed to reduce the effort force required to lift heavy objects. It consists of multiple pulleys, with one pulley attached to a fixed point and another pulley attached to the load being lifted. By distributing the load's weight across multiple pulleys, the force needed to lift the load is reduced. This makes it easier to lift heavy objects and is commonly used in various applications, such as construction, sailing, and lifting equipment.
13.
Two simple machines that are part of a bicycle are _____________
Correct Answer
C. A gear and a wheel and axle
Explanation
The correct answer is a gear and a wheel and axle. These two simple machines are commonly found in bicycles. A gear is used to transfer and adjust the speed and torque of the bicycle, allowing the rider to pedal efficiently. A wheel and axle are used to rotate the wheels, providing the movement and transportation. Both of these simple machines play crucial roles in the functioning of a bicycle.
14.
Which of the following groups of simple machines represent variations of the lever?
Correct Answer
B. Pulley, wheel and axle
Explanation
The pulley and the wheel and axle are both variations of the lever. A lever is a simple machine that consists of a rigid bar or beam that is able to rotate around a fixed point called a fulcrum. In the case of a pulley, the lever is a rope or chain that is able to rotate around a fixed point. In the case of a wheel and axle, the lever is a rod or axle that is able to rotate around a fixed point. Both of these variations utilize the principle of leverage to multiply or change the direction of a force.
15.
The MA of a single fixed pulley is always one because
Correct Answer
A. The pulley changes only the direction of the effort force
Explanation
A single fixed pulley changes only the direction of the effort force. It does not change the size, speed, or direction of the force. The pulley simply redirects the force applied to it, allowing the user to pull downwards or upwards instead of horizontally. As a result, the mechanical advantage (MA) of a single fixed pulley is always one, as there is no multiplication or reduction of the applied force.
16.
Which of the following CANNOT be done by a simple machine?
Correct Answer
B. Increase the amount of work being done
Explanation
A simple machine is a device that can change the direction of a force, decrease the time it takes to do work, and transfer energy from one location to another. However, it cannot increase the amount of work being done. This is because a simple machine can only multiply or redistribute the input force, but it cannot create additional work or energy. Therefore, increasing the amount of work being done is not possible with a simple machine.
17.
A machine that changes only the direction of a force has an MA of ______________
Correct Answer
D. 1
Explanation
A machine that changes only the direction of a force has a mechanical advantage (MA) of 1. This means that the machine does not multiply or increase the force applied, but simply changes its direction. In other words, the input force and the output force are equal in magnitude, resulting in an MA of 1.
18.
What is the IMA of the inclined plane below?IMA = Effort Distance/Resistance DistanceActual MA = Resistance Force/ Effort ForceW = FxDWin = Fe x DeWout = Fr x DrWin = WoutEfficiency = Wout/Win x 100
Correct Answer
B. 3
Explanation
The answer is 3 because the formula for IMA (Ideal Mechanical Advantage) is Effort Distance divided by Resistance Distance. However, the given information does not provide the values for Effort Distance and Resistance Distance, so we cannot calculate the exact IMA. Therefore, the answer remains as 3, indicating that the IMA is equal to 3.
19.
What is the IMA for this pulley system?
Correct Answer
B. 2
Explanation
The IMA (Ideal Mechanical Advantage) for a pulley system is the ratio of the output force to the input force. In this case, the IMA is 2, which means that for every unit of input force applied, the system will produce 2 units of output force. This indicates that the pulley system provides a mechanical advantage of 2, making it easier to lift or move heavy objects.
20.
Which pulley system will require the greatest effort distance to raise the resistance force 1 meter?
Correct Answer
B. System B
Explanation
System B will require the greatest effort distance to raise the resistance force 1 meter because it has a larger number of pulleys compared to System A. In a pulley system, the more pulleys there are, the greater the mechanical advantage, which means less effort is required to lift a load. Therefore, System A will require less effort distance compared to System B.
21.
Which lever below is a first class lever?
Correct Answer
A. Lever A
Explanation
Lever A is a first-class lever because it has the fulcrum (pivot point) located between the effort force and the load. In a first-class lever, the effort force and the load are on opposite sides of the fulcrum, and the lever can either multiply force or multiply distance depending on the relative positions of the effort and load.
22.
Which lever below is a second class lever?
Correct Answer
B. Lever B
Explanation
A second class lever is a lever where the load is located between the fulcrum and the effort. In this case, Lever B is the correct answer because the load is positioned between the fulcrum and the effort.
23.
Which lever below is a third class lever?
Correct Answer
C. Lever C
Explanation
Lever C is a third class lever because in a third class lever, the effort force is applied between the fulcrum and the load. In this case, the fulcrum is located at one end of Lever C, the load is located at the other end, and the effort force is applied in between. This arrangement is characteristic of a third class lever.
24.
Which lever below has the greatest mechanical advantage?
Correct Answer
A. Lever A
Explanation
Lever A has the greatest mechanical advantage because it has a longer distance from the fulcrum to the point where the input force is applied. This longer distance allows for a smaller input force to exert a larger output force, making it easier to lift or move heavy objects.
25.
The ___________________ is an example of a second class lever.
Correct Answer
B. Wheel barrow
Explanation
A second class lever is a type of lever where the load is located between the fulcrum and the effort. In the case of a wheelbarrow, the load (the items being carried) is placed in the front of the wheelbarrow, the fulcrum is the wheel, and the effort is applied at the handles. When the effort is applied at the handles, it creates a mechanical advantage, allowing the user to easily lift and move heavy loads. Therefore, the wheelbarrow is an example of a second class lever.
26.
The _________________ is an example of a third class lever.
Correct Answer
A. Fishing pole
Explanation
A third class lever is a type of lever where the effort is applied between the fulcrum and the load. In the case of a fishing pole, the fulcrum is the hand holding the pole, the effort is applied by the angler's hand, and the load is the weight of the fish or resistance in the water. Therefore, a fishing pole is an example of a third class lever.
27.
Which lever below has the greatest mechanical advantage?
Correct Answer
B. Lever B
Explanation
Lever B has the greatest mechanical advantage because it has a longer distance from the fulcrum to the point where the input force is applied, compared to the other levers. This longer distance allows for a smaller input force to generate a larger output force, making it easier to lift heavier objects.
28.
What letter represents the resistance force?
Correct Answer
A. A
Explanation
The letter "A" represents the resistance force.
29.
What letter represents the effort distance?
Correct Answer
D. D
Explanation
The letter D represents the effort distance.
30.
If the effort distance of a first class lever is 0.10 meters and the effort force is 2.5 N, what is the work input of the simple machine? IMA = Effort Distance/Resistance DistanceActual MA = Resistance Force/ Effort ForceW = FxDWin = Fe x DeWout = Fr x DrEfficiency = Wout/Win x 100
Correct Answer
C. 0.25
Explanation
The work input of the simple machine can be calculated using the formula W = F x D, where F is the effort force and D is the effort distance. In this case, the effort force is given as 2.5 N and the effort distance is given as 0.10 meters. Therefore, the work input can be calculated as 2.5 N x 0.10 meters = 0.25 Nm or 0.25 Joules.
31.
The ideal mechanical advantage and the actual mechanical advantage will always be the same.
Correct Answer
B. False
Explanation
The statement is false because the ideal mechanical advantage and the actual mechanical advantage are not always the same. The ideal mechanical advantage is calculated based on the ideal conditions and does not take into account any losses due to friction or other factors. On the other hand, the actual mechanical advantage considers these losses and provides a more realistic measure of the effectiveness of a machine. Therefore, the ideal mechanical advantage and the actual mechanical advantage can differ depending on the specific circumstances.
32.
The work input will always be larger than the work output of a simple machine with an actual mechanical advantage greater than 1.
Correct Answer
B. False
Explanation
A simple machine with an actual mechanical advantage greater than 1 means that the machine can multiply the input force to produce a greater output force. Therefore, the work output of the machine will always be larger than the work input because work is directly proportional to force. So, the statement that the work input will always be larger than the work output of a simple machine with an actual mechanical advantage greater than 1 is false.
33.
If the resistance force is 3.15 Newtons and the resistance distance is 0.85 meters, the work output will equal ______.IMA = Effort Distance/Resistance DistanceActual MA = Resistance Force/ Effort ForceW = FxDWin = Fe x DeWout = Fr x DrEfficiency = Wout/Win x 100
Correct Answer
B. 2.68
Explanation
The work output is calculated using the formula Wout = Fr x Dr. In this case, the resistance force is given as 3.15 Newtons and the resistance distance is given as 0.85 meters. Plugging these values into the formula, we get Wout = 3.15 x 0.85 = 2.6775. Rounding this to two decimal places, we get 2.68. Therefore, the correct answer is 2.68.
34.
The comparison between work output and work input is the ideal mechanical advantage.
Correct Answer
B. False
Explanation
The comparison between work output and work input is not the ideal mechanical advantage. The ideal mechanical advantage is actually the ratio of the input force to the output force, and it is a measure of the effectiveness of a machine in amplifying force. The comparison between work output and work input is related to the efficiency of a machine, not the ideal mechanical advantage.
35.
What is the actual mechanical advantage of the machine below?Efficiency = Wout/Win x 100
Correct Answer
A. 0.08
Explanation
The actual mechanical advantage of the machine is 0.08. This is determined by dividing the output work (Wout) by the input work (Win), and then multiplying by 100 to convert it to a percentage. The given answer of 0.08 indicates that the machine has a low mechanical advantage, meaning that it does not amplify force or make work easier.
36.
To increase the IMA of an inclined plane, you can
Correct Answer
B. Increase the length or decrease the height
Explanation
To increase the IMA (Ideal Mechanical Advantage) of an inclined plane, you can either increase the length of the plane or decrease its height. This is because the IMA is calculated by dividing the length of the inclined plane by its height. By increasing the length, you are increasing the distance over which the force is applied, leading to a higher IMA. On the other hand, by decreasing the height, you are reducing the vertical distance the object needs to be lifted, which also increases the IMA.