M3 Power

Question 1

What is Power?

Answer 1

Power is the rate at which work is done and is expressed in Watts (W)

Question 2

What is the formula for power?

Answer 2

P= W/t but it can also be expressed as Fv

Question 3

Units for power?

Answer 3

Watts (W), where 1 W = 1 joule/second.

Question 4

How do you convert from watts to kilowatts?

Answer 4

Divide by 1,000. Example: 2,500 W = 2.5 kW.

Question 5

What is instantaneous power?

Answer 5

The power at a specific moment in time

Question 6

In a system with a constant force, how is average power calculated?

Answer 6

AveragePower=
Total work/Time taken
​

Question 7

What will need to be calculated for this question: Calculate the power output needed for a 900kg car to climb a 5 degree slope at a constant 90km/h while encountering wind resistance and friction totalling 500N

Answer 7

1. The force that the engine must provide the wheels for them to overcome the total resistance forces and the weight component

Question 8

What does a higher power rating in machines typically imply?

Answer 8

The machine can perform more work in a shorter time or operate under higher loads.

Question 9

What is the formula for power on an inclined plane?

Answer 9

P= Fv =mgsinθ x v
(Where v is the velocity up the incline.)