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You've got to move it!
Maynard G. Krebs
Advantage, Mechanical advantage
It's simple!
Leftovers!
100
Jorge applies a force of 100 N to move a box 5 meters. How much work did he do?
a. 100 J b. 5 J c. 500 J d. 500 N
100
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.
100
The ideal mechanical advantage for an inclined plane is equal to the length of the incline divided by the
a. mass of the incline. b. slope of the incline. c. height of the incline. d. angle of the incline.
100
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.
100
How can a hockey stick be considered a machine?
a. It multiplies force. b. It multiplies distance. c. It changes direction. d. It reduces friction.
200
If you exert a force of 20 newtons to push a desk 10 meters, how much work do you do on the desk?
a. 200 joules b. 30 joules c. 100 joules d. 10 joules
200
If a barbell weighs 160 N, what other information do you need to calculate how much work it takes to lift it?
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.
200
The ideal mechanical advantage of a wheel and axle is equal to the
a. radius of the wheel divided by the radius of the axle. b. radius of the axle divided by the radius of the wheel. c. radius of the wheel divided by the length of the axle. d. length of the axle divided by the radius of the wheel.
200
Which of the following simple machines is NOT a wedge?
a. Knife b. Plow c. Chisel d. Ramp
200
If tight scissors have an efficiency of 50 percent, half of your work is wasted due to
a. the output force. b. the input force. c. friction. d. changes in direction.
300
Which of these is an example of work being done on an object?
a. holding a heavy piece of wood at a construction site b. trying to push a car that doesn’t move out of deep snow c. pushing a child on a swing d. holding a door shut on a windy day so it doesn’t blow open
300
5. 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.
300
The mechanical advantage of a machine that changes only the direction of force is
a. 1. b. less than 1. c. greater than 1. d. 0.
300
What does a fixed pulley change?
a. The speed of a force b. The direction of a force c. The size of a force d. The timing of the force
300
Which of the following is a compound machine?
a. First class lever b. Block and tackle c. Wheel and axle d. Screw
400
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.
400
When a machine increases the size of the force exerted, what happens to the distance?
a. It must increase b. It must decrease c. It must stay the same d. It must double
400
By comparing the mechanical advantage of two machines that have the same output force, what can you tell about the machine?
a. Which is bigger. b. Which has a larger input force. c. Which has a larger output force. d. Which makes work easier.
400
Pulling down on a rope to hoist a sail on a sailboat is an example of a machine
a. multiplying the force you exert. b. multiplying the distance over which a force is exerted. c. changing the direction over which a force is exerted. d. reducing friction.
400
What type of simple machine is a screw?
a. Inclined plane b. Wheel and axle c. Lever d. Pulley
500
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. 5 J b. 50 J c. 5 W d. 50 W
500
Without friction there would be
a. less machine efficiency. b. greater output work than input work. c. greater input work than output work. d. equal input and output work.
500
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. 20 c. 1 d. 40
500
The mechanical advantage of a machine is the number of times a machine increases
a. the distance an object is moved. b. the amount of friction. c. the change in direction. d. the force exerted on the machine.
500
Which of the following machines always has a mechanical advantage of less than 1?
a. Wheel and axle b. Third-class lever c. A long, thin wedge d. A poorly lubricated, movable pulley