1. Topic 2 – Mechanics 2.2 – Forces and Dynamics

7. F is the surface friction force acting along the surface from the point of contact .

10. R is the normal reaction force of the ramp on the box acting perpendicular to the surface of contact from the point of contact .

11. F is the surface friction force acting along the surface from the point of contact .

13. This will help identify Newton's third law paired internal forces and help solve the problem.

15. Gravity is a field. The slope of that field is the gravitational field strength.

16. The effect of the field on an object's mass is called the object's weight due to gravity.

17. Weight is a force and is measured in newtons.

20. M : inetial mass in kg

22. G = 9.81 Nkg -1 or 9.81 ms -2

24. The velocity is constant or zero

25. There is no change in direction.

28. m : the inertial mass of the object in kg

30. The acceleration will be in the same direction as the nett force.

33. m = inertial mass in kg

36. A 1000kg car travelling at 30ms -1 to the left.

37. A 50,000kg rocket travelling at 80ms -1 upwards.

40. The product of force and time is called impulse and is measured in Ns

42. The total impulse is found in reality by measuring the area under an F-t graph

44. A cricket ball has a velocity of 130kmh -1 when bowled. The batsman applies an impulse of 350Ns to the 160g ball. What is the speed of the ball after striking?

49. You can not “measure” these forces, but you can calculate them.

51. Are of the same type (contact, gravitational etc)

52. Are of the same magnitude

55. What is the magnitude of the force exerted on Box B by box A?