BMAT Motion, Energy, Work, Power, Conservation of Energy Sheet

A car accelerating constantly at 5 m s^-2. If its velocity changes from 10 m s^-1 to 25 m s^-1, calculate the time taken to reach final velocity.

• 1 s

• 4 s

• 2 s

• 3 s

A car is capable of accelerating at 0.60 m s^-2. Calculate the time needed for this car to go from speed of 5.5 m s^-1 to a speed of 8.0 m s^-1.

• 4.17 s

• 8.34 s

• 1.03 s

• 16.67 s

A car initially at rest, starts moving with a constant acceleration of 0.6 ms^-2 and travels a distance of 30 m. Calculate its final velocity.

• 6 ms^-1

• 16 ms^-1

• 2 ms^-1

• 0.8 ms^-1

An engine does 300 J of work in 10 seconds. How much power did it use?

• 3000 N

• 3000 W

• 30 W

• 30 J

How much work is done by lifting an object with a weight of 250 N a total of 2 m off the ground?

• 125 J

• 125 W

• 500 W

• 500 J

If Mr. P’s dog Ally has a mass of 50 kg and runs up a flight of stairs with a height of 10 meters in 2 seconds and Ms. Poteete’s dog Jasper has a mass of 25 kg and runs up the same flight of stairs in the same amount of time. Which dog has more power?

• Jasper

• Ally

• Air Bud

• Scout

If a light bulb with an efficiency of 80% lights up the room and 16 J of energy is converted to light energy and 4 J of energy is lost to thermal energy. What is the total energy in the system?

• 80%

• 4 J

• 20 J

• 16 J

An engine has an inout of 5000 W. The useful output is 4000W. Calculate its percentage efficiency.

• 90%

• 80%

• 75%

• 85%

Two workers use 100 N of force to move a sofa 2 meters in 2 seconds. How much power is required?

• 100 watts

• 400 watts

• 104 watts

• 50 watts

If a group of workers can apply a force of 1,000 Newtons to move a crate 20 meters, what amount of work will they have accomplished?

• 20,000 J
• 200 J
• 2,000 J
• 20 J