Work and power Flashcards
1
Q
When is Work done?
A
Work is done when a force moves an object in the direction in which the force acts.
2
Q
Work done Formula
A
work done = force x distance moved (in the direction of the force)
3
Q
What is weight?
A
- Weight is a measure of the gravitational attraction on a body acting towards the centre of the earth.
- A mass of 1 kg has a weight of about 10 N on Earth.
4
Q
Weight Formula
A
weight = mass x gravitational field strength
5
Q
What is Power?
A
Power is the rate at which work is done.
6
Q
Power Formula
A
Power = work done/ time taken (s)
7
Q
work done (p) Eq.
A
work done = power x time (s)
8
Q
time taken Eq.
A
time taken (s) = work done / power
9
Q
1 MW to W
A
1,000,000
10
Q
When is a person’s power greater?
A
A person’s power is greater when they run than when they walk.
11
Q
Some cars are more powerful than others…
A
- They travel faster and cover the same distance in a shorter time and require more fuel. The power rating of a car depends on its engine size. More powerful cars have a greater fuel consumption.
- Fuel is expensive and a car with a high fuel consumption is expensive to run.
12
Q
How do fuels pollute the environment?
A
- Car exhaust gases, especially carbon dioxide, are harmful.
- Carbon dioxide is also a major source of greenhouse gases, which contribute to climate change
13
Q
Power 1
A
Power = (force x distance) / time
14
Q
Power 2
A
Power = force x speed
15
Q
Power 3
A
power = force x distance/time
