Across
- 6. 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.
- 10. Every action has an equal and opposite reaction. If an object A exerts a force on object B, object B will exert a force of equal magnitude but of opposite direction on object A.
- 13. A quantity with magnitude and direction (e.g. velocity, acceleration, force).
- 15. The resistance against the motion of an object through a fluid. It is usually proportional to the speed of the object.
- 16. Force The sum of all forces on an object.
- 20. The change of momentum of an object when a force acts on it. Equal to the area underneath a force-time graph.
- 21. 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.
- 23. the resultant force on the object is zero.
- 24. A force applied over a distance, it is the energy transferred in that distance.
- 26. 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.
- 28. The energy gained by an object when it is raised by a height in a gravitational field.
Down
- 1. The force of gravity on an object, the product of the object’s mass and the acceleration due to gravity.
- 2. 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.
- 3. A force acting perpendicular to the flow of air or liquid around an object, typically upwards and against the force of gravity.
- 4. The product of an object’s mass and its velocity.
- 5. Any object acted upon only by the force of gravity
- 7. When the kinetic energy of a system before an event is equal to the kinetic energy of the system after the event.
- 8. 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.
- 9. If an object is acted upon by a resultant force it will accelerate. The acceleration is inversely proportional to the mass of the object and directly proportional to the force acting upon it.
- 11. The useful output (e.g. power, energy) of a system divided by the total output
- 12. An object is at equilibrium when the moments on it about a point are balanced
- 14. The maximum velocity an object can achieve. It is the point at which frictional forces and driving forces are balanced and so no acceleration occurs and the resultant force on the object is 0 N.
- 17. 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.
- 18. The rate of change of momentum of an object. The product of the object’s mass with its acceleration.
- 19. The work done by a system divided by the time taken for that work to be done.
- 22. An object at a constant velocity will remain at a constant velocity unless acted on by an external resultant force.
- 25. The product of a force and the perpendicular distance from the line of action to the pivot about which the force is acting.
- 27. A quantity with only magnitude and no direction (e.g. mass, energy, length).