Unit 9: Work, Simple Machines, Mechanical Advantage Review

How can you decrease the effort force needed to push a weight to the top of the ramp? 

• cover the surface with carpet
• increase the length of the ramp
• increase the height of the ramp
• decrease the length of the ramp

A 62 kg box is lifted 12 m off the ground. How much work was done? (hint: calculate F_w first)

• 5.17 J
• 72.91 J
• 744.0 J 
• 7291.2 J

Calculate the amount of work done if you use a 100N force to push a 50 kg box 5 m across the kitchen floor. 

• 250 J 
• 500 J
• 5000 J
• 50,000 J

Jeff is a landscaping contractor and lifts a rock weighing 600 pounds by wedging a board under the rock. Jeff weighs 150 pounds and puts all of his weight on the lever. How much mechanical advantage did the lever provide to Jeff in lifting the rock?

• 0
• 2
• 4
• 8

Using a lever, Joe is able to lift a 10,000 N car off of the ground with a force of 1000 N. What is the mechanical advantage of the lever?

• 1
• 10
• 100
• 1000

A 16 N force is applied to an object and 96 J of work is done. How far was the object moved?

• 6 m
• 16 m 
• 80 m 
• 1536 m 

A lever and fulcrum are used to lift a fallen tree, which has a weight of 480 N. If the lever has a mechanical advantage of 5.5, what is the input force that will begin lifting the tree off the ground?

• 5.5 N
• 40.7 N
• 87.3 N
• 2640 N

To lift a load off the ground, the force required is equal to the weight of the load. In case of a lever, however, a small effort force can be used to lift a much heavier load. How is this possible?

• Levers use the weight of the load combined with the effort to lift the load.
• Levers combine the weight of the load with the force of gravity to lift the load.
• Levers reduce the force required by increasing the distance over which the force is applied.
• Levers distribute the load over their length, thereby reducing the force required to lift the load.

This 2000 N weight is raised 1 meter by pulling 4 meters of rope. What force was required to pull the rope?

• 500 N
• 1000 N
• 2000 N
• 8000 N

What is the primary mechanical advantage of using the simple machine seen in the image?

• You can apply a small input force and have it multiplied into a large output force.
• You can apply a large input force and have it multiplied into a small output force.
• You can apply a small input distance and have it multiplied into a large output distance.
• You can apply a large input distance and have it multiplied into a small output distance.