physics 2.2

physics 2.2

1. when a force moves an object through a distance then work is tone and energy transferred

2. work done and energy is measured in joules.

3. work done = energy transferred

4. work done= force x distance moved

5. power is the work done in a given time, it is measured in watts.

6. power=energy transferred

7. GPE is the energy an object gains when it is lifted up ina gravitational field

8. change in GPE height= massx gravitational field stregth x change in metres

9. the kinetic energy of an object depends on its mass and speed measured in joules

10. momentum before = momentum after

    • momentum= mass x velocity

11. weight depends on gravitational field strength

    • mass is the amount of stuff in an object
      • the gravitational field strength on Earth is 10n/kg
        • weight = mass x gravitational field strength

12. when an object has increased speed the air resistance is bigger and the force is smaller

    • when a parachute is deployed it gives a large surface area and a large resultant force causing the object to decelerate

13. the air resistance is small when an object starts to fall as it is traveling slowly

    • as the object accelerates the air resistance increases but the weight stays the same
      • when the air resistance is the same size as the weight the resultant force is 0 so the objact has reached terminal velocity