• A device that makes work easier by changing the size or direction of force is called what? A. power B. machine C. watt D. force
• What is the work that you do on a machine called?
• What is the number of times the machine multiplies force called?
A. power B. work output C. work input D. lever
A. power B. mechanical efficiency C. output force D. mechanical advantage
• Which equation would you use to find mechanical advantage?
• Which of the following prevents machines from being 100% efficient?
A. MA = work output/work input x 100 B. MA = work input/work output x 100 C. MA = output force/input force D. MA = input force/output force
A. friction B. output force C. input force D. power
• What is the work done by a machine on an object called? A. power B. work output C. work input D. lever
• Which of the following is a comparison of a machine’s work output with the work input? A. mechanical efficiency B. mechanical advantage C. force D. power
• In which situation is a person doing work on an object? A. A school crossing guard raises a stop sign that weighs 10 N. B. A student walks while wearing a backpack that weighs 15 N. C. A man exerts 350 N force on a rope attached to a house. D. A worker holds a box 1 m off the floor.
• Which of the following simple machines were used by the Egyptians to build pyramids?
• If a barbell weighs 160 N, what other information do you need to calculate how much work it takes to lift it?
A. screws and screwdrivers B. plows and axes C. inclined planes and levers D. wheels and axles
A. the shape of the weights B. how high the barbell is being lifted C. the strength of the person doing the lifting D. the amount of output force
• If two people lift identical stacks of books the same distance and one person does the job twice as fast, which of the following has doubled?
• By comparing the mechanical advantage of two machines that have the same output force, what can you tell about the machine?
A. work input B. power C. work output D. efficiency
A. which is bigger B. which has a larger output force C. which has a larger input force D. which makes work easier
• Which of the following simple machines is NOT a wedge?
• Greg applies a force of 100 N to move a box 5 meters. How much work did he do?
A. knife B. chisel C. plow D. ramp
A. 100 J B. 5 J C. 500 J D. 500 N
• How does a ramp make lifting a heavy object easier? A. The object is moved over a shorter distance. B. The ramp increases the amount of work you do. C. Less force is needed to move the object over a longer distance. D. More force is needed to move the object over a longer distance.
• Why is the work output of a machine always less than the work input? A. Some work is used to get the machine started. B. Some work is used to overcome the friction created by the machine. C. Some work is used to keep the machine running. D. There isn’t enough power present.
• If you exert 20 N of force on a screwdriver and it exerts 40 N on a paint can lid, what is the screwdriver’s mechanical advantage? A. 2 B. 1 C. 20 D. 40
• Which of the following is a compound machine? A. first‐class lever B. wheel and axle C. block and tackle D. screw
• Which of the following machines always has a mechanical advantage of less than 1? A. wheel and axle B. a long, thin wedge C. third‐class lever D. a poorly lubricated, movable pulley
• What type of simple machine is a screw? A. inclined plane B. lever C. wheel and axle D. pulley
• Which of the following must happen for work to be done? A. The object must move, and there must be an output force. B. The object must move in the opposite direction of the force. C. The object must move in the same direction as the force. D. The object must move, and the mechanical advantage must be greater than 1.
• What does a fixed pulley change? A. the speed of a force B. the size of a force C. the direction of a force D. the timing of the force
• What is it called when a force causes an object to move in the direction of the force? A. energy B. work C. force D. power
• A construction worker is lifting a load of bricks onto a truck and he does 200 J of work in 40 s. What is his power output? A. 50 J B. 50 W C. 5 J D. 5 W
• When a machine increases the size of the force exerted, what happens to the distance? A. It must increase. B. It must stay the same. C. It must decrease. D. It must double.
• The rate at which energy is transformed is called what? A. power B. work C. energy D. joule
• What is a machine that is made of two simple machines called?
• What is a machine with a grooved wheel that holds a cable called?
A. simple machine B. pulley C. lever D. compound machine
A. lever B. wheel and axle C. pulley D. wedge
• Chris and Jane are lifting boxes to put them on shelves. Chris does 200 J of work in 5 min, and Jane does 200 J of work in 4 min. What is the difference between the two jobs?
• When a screwdriver is used as a lever to open a paint can, what is changed as the work is done?
A. the input force B. the work C. the output force D. the power
• The greater the ratio of an inclined plane’s length to its height, the greater the A. mechanical efficiency. B. work. C. mechanical advantage. D. power.
A. size of the input force B. size and direction of the input force C. direction of the input force D. power
• the type of energy that a moving object has A. kinetic energy B. work C. power D. watt
• Which of the following would increase the mechanical advantage of a first‐ class lever? A. applying a greater input force B. increasing the rate at which force is applied C. decreasing the load D. moving the fulcrum closer to the load
• A doorknob is an example of a A. pulley. B. lever. C. wheel and axle. D. screw.
• the unit used to express power A. kinetic energy B. work C. power D. watt
• the unit used to express energy
• a fixed point on a lever
A. kinetic energy B. work C. power D. watt
A. pulley B. fulcrum C. wheel and axle D. lever
• a simple machine that has a grooved wheel that holds a rope
• a simple machine that is made up of two inclined planes and that moves
• a simple machine that is a straight, slanted surface
A. pulley B. fulcrum C. wheel and axle D. lever
A. lever B. inclined plane C. wedge D. pulley
A. inclined plane B. wedge C. wheel and axle D. fulcrum
• a simple machine that has a bar that pivots at a fixed point
• Lever A is an example of which type of lever
• Lever B is an example of which type of lever
A. first class lever B. second class lever C. third class lever
A. first class lever B. second class lever C. third class lever
• the transfer of energy using a force that causes an object to move in the direction of the force A. kinetic energy B. work C. power D. watt
A. pulley B. fulcrum C. wheel and axle D. lever
• Lever C is an example of what type of lever. A. first class lever B. second class lever C. third class lever