Work and Power Practice

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.

Formula of work:

• W = F x t

• W = F + t

• W = F / d

• W = F x d

Tags

NGSS.MS-PS3-5

Units of work is ___________

• Newton (N)

• watt (w)

• joule (J)

Tags

NGSS.MS-PS3-5

Power is ___________

• Is the rate of energy transfer.

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

• both

• none

Tags

NGSS.MS-PS3-5

Power =

• Work + time

• Work / time

• Work x time

1. A book weighing 1.0 newton is lifted 2 meters.  How much work was done?

• 2 J
• 0.5 J

A force of 15 newtons is used to push a box along the floor a distance of 3 meters.  How much work was done?

• 3 J
• 45 J

It took 50 joules to push a chair 5 meters across the floor. With what force wast the chair pushed?

• 250N
• 10N

Tags

NGSS.MS-PS2-2

It took 500 newtons of force to push a car 4 meters.  How much work was done?

• 2,000 J
• 125 J

A young man exerted a force of 9,000 newtons on a stalled car but was unable to move it.  How much work was done?

• 9,000 J
• 0 J= No work