Work Done and Power

A student needs 10 Newtons of force to lift a box to the top of a 2 meter shelf. How much work do they do?

• 12 J

• 8 J

• 20 J

• 5 J

Tags

NGSS.MS-PS3-5

A soccer player kicks a ball with 20 Newtons of force causing it to travel 100 meters. How much work is done on the ball?

• 200 J

• 80 J

• 5 J

• 2000 J

Tags

NGSS.MS-PS3-4

P=25 watts 
W=5000 Joules 
t=???

• 200 sec

• 0.0005 s

• 125000 s

• 125 s

A man lifts three boxes together from the ground on to a shelf that is 1.5 m above the ground. The weight of the boxes is 300 N and the man takes 2.0 s to lift them.

How muck power does the man produce to lift the boxes?

• 75 W

• 225 W

• 300 W

• 900 W

Tags

NGSS.MS-PS2-4

Four different children run up the same set of stairs. For which child is the useful power to climb the stairs the GREATEST?

• Child A

• Child B

• Child C

• Child D

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-4

NGSS.MS-PS3-5

A 70 kg student travels from the first floor to the fourth floor of a school (a

height of 25 m).

What total work did she do to climb the stairs?

How long would this trip last if the student produced 250 W of

power?

Tags

NGSS.MS-PS3-2

NGSS.MS-PS3-4

NGSS.MS-PS3-5

What is the equation used to calculate Work?

• W = m . v

• W = F . d

• W = F / d

• W = m . v²

Tags

NGSS.HS-PS3-3

The diagram shows the energy used by a modern lamp. Which expression gives the efficiency of the lamp?

• (12/60) x 100%

• (12/48) x 100%

• (48/60) x 100%

• (48/12) x 100%

Tags

NGSS.MS-PS3-4

How much work is done in holding a 15 N sack of potatoes while waiting in line at the grocery store for 3 minutes?

• 15 J

• 45 J

• 0 J

• 5 J

What is the work output of a machine that has a work input of 2,800 Joules and an efficiency of 90%?

• 25200 J

• 2520 J

• 0.0082J