Extra Physics flashcards January 2023

Question 1

16. A number of forces acting on an object may be replaced by a single force that has the same effect as all the original forces acting together. This single force is called the ……………… force.

Answer 1

resultant

Question 2

17. What is the resultant force when the forces on an object are balanced?

Answer 2

Zero or 0 N

Question 3

18. State the effect of unbalanced forces on a moving object if the resultant force direction is in the direction that the object is moving. Which one of the following is true? 1) It will stay stationary 2) It will keep moving at a constant speed 3) It will speed up 4) It will slow down

Answer 3

3) It will speed up

Question 4

19. State the effect of balanced forces (zero resultant) on a moving object. Which one of the following is true? 1) It will stay stationary 2) It will keep moving at a constant speed 3) It will speed up 4) It will slow down

Answer 4

2) It will keep moving at a constant speed

Question 5

20. State the effect of balanced forces (zero resultant) on a stationary (not moving) object. Which one of the following is true? 1) It will stay stationary 2) It will keep moving at a constant speed 3) It will speed up 4) It will slow down

Answer 5

1) It will stay stationary

Question 6

21. State the effect of unbalanced forces on a stationary (not moving) object. Which of the following is true? 1) It will stay stationary 2) It will keep moving at a constant speed 3) It will speed up 4) It will slow down

Answer 6

3) It will speed up

Question 7

22. State the effect (if any) of unbalanced forces on a moving object if the resultant force is in the opposite direction to the direction of the moving object. Which one of the following is true? 1) It will stay stationary 2) It will keep moving at a constant speed 3) It will speed up 4) It will slow down

Answer 7

4) It will slow down

Question 8

37. Why do surfaces that feel smooth still have friction?

Answer 8

Even smooth surfaces have microscopic hills and valleys (which resist movement)

Question 9

38. What force causes surfaces to wear away over time?

Answer 9

friction

Question 10

39. In addition to wearing away surfaces what other effect does friction cause when rubbing two objects together?

Answer 10

A rise in temperature

Question 11

40. Describe 2 uses of friction between solids

Answer 11

Without friction our feet would not be able to grip the road and we would be unable to walk / Friction is important in helping objects to slow down safely using brakes / [Also to strike a match]

Question 12

41. Describe a benefit of air resistance

Answer 12

Air resistance is the force that parachutes make use of to slow down someone who is falling from an aeroplane

Question 13

42. Why doesn’t a rocket in space need to use its engine to keep moving?

Answer 13

There is no friction or air resistance in space to slow it down. [Gravity is not zero in space]

Question 14

43. State the equation for speed

Answer 14

Speed = Distance/Time

Question 15

44. When distance is measured in metres and time is measured in seconds, what is speed measured in?

Answer 15

m/s

Question 16

45. Calculate the speed of an object moving a distance 10 m in 2 s.

Answer 16

Speed = Distance/ Time= 10 /2 = 5 m/s

Question 17

46. What word is used to describe an object that is speeding up?

Answer 17

Acceleration or accelerating

Question 18

47. For a spring what do we call the stretched length minus the unstretched length?

Answer 18

Extension

Question 19

48. What is the name of the law that springs obey? The law says that a spring’s extension doubles when the force doubles or extension is directly proportional to the stretching force.

Answer 19

Hooke’s Law

Question 20

49. Describe a risk assessment for the spring experiment

Answer 20

Hazard: Spring could break or come loose / Risk: damage eye / Precaution: Wear safety goggles