Elastic Potential Energy and Power

A person weighing 600 N gets on an elevator. The elevator lifts the person 6 m in 10 seconds.  How much power was used?

• 360 W 
• 60 W
• 3600 W
• 600 W

Tags

NGSS.MS-PS2-4

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

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

• 0.25 Joules
• 26%
• 3.86 Joules
• 386%

measures the ratio of work output to work input

• joules
• power
• work
• efficiency

How are work and and power related?

• if work is increased than the power generated is decreased
• there is not enough information given to know the answer
• if work is increased than power is increased
• work and power are not related

What units are used to measure power?

• watts
• Joules
• meters
• newtons

If you buy a machine that has an efficiency of 82%, what happened to the other 18%?

• The energy was lost to friction, heat and other forms of energy
• There is not enough information given

Tags

NGSS.MS-PS3-5

How much force will it take to get the block of ice in this diagram to a height of three meters if it is pushed up the ramp. It has a weight of 100 N

• 25 N
• 50 N
• 75 N
• 200 N

A person pushes a lawn mower using 2000 J of energy a distance 40 m across a lawn against a friction force of 15 N. How much of their 2000J was converted to heat?

• 600 J
• 200 J
• 350 J
• 1200 J

An old clock has a spring that must be wound to make the clock hands move. Which statement describes the energy of the spring and hands of the clock?

• The spring has kinetic energy and the hands have kinetic energy.
• The spring has kinetic energy and the hands have potential energy. Option 2*
• The spring has potential energy and the hands have potential energy.
• The spring has potential energy and the hands have kinetic energy.