What is meant by work done | Work done is a way of transferring energy from one object to another |
Define energy | That which is transferred when a force moves through a distance |
When pushing a car along a road what are the 2 factors involved in calculating how much work you are doing? | 1. Size of the force F
- Bigger the force, the greater the amount of work you do
2. Distance s you push the car
- The further you push it the greater the amount of work done |
Work done by a force is defined as? | The product of the force and the distance moves in the direction of the force
W = F x s |
What is the SI unit for both energy and work | joule (J) |
The amount of work done, using W = F x s, shows what? | Energy transferred |
Define Joule (J) | Amount of work done when one force of 1 newton moves a distance of 1 meters in the direction of the force |
Work done by the force depends on the angle between the force and the distance it moves. What is the formula? | Fs cosθ |
When energy is transferred from you to the object. The what of the object has increased? | gravitational potential energy, E`p |
What is the formula for gravitational potential energy | gravitational potential energy g.p.e = weight x change in height
△E`p = mg△h |
In the equation △E`p = mg△h what does the h stand for? | h stands for the vertical height through which the object moves |
What is potential energy | Energy an object has because of its position or shape |
What is the formula for kinetic energy | 1/2 x mass x speed^2 |
A decrease in g.p.e means what | an increase in k.e |
What is the formula for calculating efficiency? | (useful output energy ➗ total input energy) ✖️ 100 |
Energy can not be created or destroyed but it can be | converted from one form to another |
Define power | rate of work done per unit of time |
Define watt | rate of working 1 joule per second |
Power is measured in (1), named after (2), the scottish engineer famous for development of the (3)in the second half of the 18th century | 1. Watts
2. James Watt
3. Steam engine |
Power can also be calculated using this equation | force x velocity |