Across
- 3. The resistance against the motion of an object through a fluid. It is usually proportional to the speed of the object.
- 6. When the kinetic energy of a system before an event is not equal to the kinetic energy of the system after the event. The kinetic energy has been transferred to other forms.
- 8. The average point of all parts of an object weighted according to their mass. It is the point through which the total mass of the object is said to act.
- 9. The change of momentum of an object when a force acts on it. Equal to the area underneath a force-time graph.
- 10. The resistance against the motion of an object. This could be caused by the air passing over the object or by the contact of the object with the surface it is moving on.
- 11. The useful output (e.g. power, energy) of a system divided by the total output.
- 12. In a closed system with no external forces the momentum of the system before an event is equal to the momentum of the system after the event.
- 13. The rate of change of momentum of an object. The product of the object’s mass with its acceleration.
Down
- 1. When the kinetic energy of a system before an event is equal to the kinetic energy of the system after the event.
- 2. The energy gained by an object when it is raised by a height in a gravitational field.
- 4. The energy an object has due to its motion. It is the amount of energy that would be transferred from the object when it decelerates to rest.
- 5. In a closed system with no external forces the energy of the system before an event is equal to the energy of the system after the event. The energy does not need to be in the same form after the event as it was before the event
- 7. An object is at equilibrium when the moments on it about a point are balanced and the resultant force on the object is zero