Chapter 8 - Work and power - Part 3

How much time is needed to produce 720 Joules of work if 90 watts of power is used? 

• 0.125 s
• 8 s
• 64800 s
• 80 s

If 68 Joules were necessary to move a 4 Newton crate, how far was the crate moved?

• 272 m
• 17 m
• 4.05 m
• 272 cm 

The unit used to measure power is the 

• Watt
• Newton
• Joule
• Newton*meter

the ability to do work or cause change

• work

• force

• motion

• energy

When we use force to move things, we do ______.

• work

• force

• power

In which of these scenarios is WORK being done? 

• a student pushes a locked door that does not move

• a student carries his chair into another room

• a student sleeps

Work is done ___________

• only when force is applied

  on an object

  cause the object to move

  into the opposite direction

  as applied force.

• only when force is applied

  on an object

  cause the object to move

  into the same direction

  as applied force.

There are two condition of work to be done....

• Constant applied force on the object

• Object travel a distance in the same direction of force

• Both

Power is ___________

• Is the rate of energy transfer.

• Speed of doing work is work done in a certain time.

• both

• none

Mechanical Efficiency =

• "Output work" / "Input work"   x 1%

• "Output work" / "Input work"   x 10%

• "Output work" / "Input work"   x 100%