Work, Power, AMA, IMA, Efficiency

What is a simple machine?

• a device that has only one working motor
• a device that makes work easier
• a device that makes more work for a job
• device that is made up of two or more machines

How could I reduce the effort force needed to lift the weight?

• move the fulcrum (triangle) away from the load

• move the fulcrum (triangle) closer to the load

• place the fulcrum (triangle) in the middle

How much work is done if I use 5 Newtons to move an object 2 meters?

• 10 Newtons
• 10 meters
• 10 Joules
• 7 Joules

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

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

Tags

NGSS.HS-PS2-1

The input force is 20 and the output force is 4.  What is the mechanical advantage?

• 80
• 5
• .2

Tags

NGSS.HS-PS2-1

What is the efficiency of the machine if the input is 263 J and the output is 142 J? 

• 6.26%
• 54%
• 100%
• 260%

Tags

NGSS.HS-PS3-1

What is the efficiency of a machine if 55.3 J of work are done on the machine, but only 14.3 J is produced by the 1machine?

• 0.25 J
• 26%
• 386%
• 3.86 J

Tags

NGSS.HS-PS3-1

A measurement of how much energy is conserved in a machine.

• efficiency

• power

• input force

• mechanical advantage

What happens when you have a short inclined plane?

• It takes less work to pull something
• It takes more work to pull something
• Nothing happens
• You have to accelerate to pull something