# 1111 2222 3333 4444 5555 6666 7777 8888 9999 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26.

## Presentation on theme: "1111 2222 3333 4444 5555 6666 7777 8888 9999 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26."— Presentation transcript:

1111 2222 3333 4444 5555 6666 7777 8888 9999 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

1. What two measurements are needed to calculate the average speed of an object? Distance and Time answer

2. What equation would be used to calculate average speed? Speed = distance / time answer

3. A trolley takes 1.5 s to travel 60cm Calculate its average speed.. v = d/t = 60 / 1.5 = 40 cm/s answer

4. Does a car speedometer give average or instantaneous speed? instantaneous answer

5. Give one advantage of using an electronic timer rather than a hand held stopwatch. Removes effect of reaction time answer

6. What is meant by the term acceleration? Change in speed per second answer

7. Acceleration is measured in metres per second per second. Write this in symbol form. m/s/s or m/s 2 or ms -2 answer

8.What equation is used to find acceleration? a = (v-u)/t answer

9. An object starts from rest and reaches 8m/s after 4s. Find the acceleration. a = (v-u) / t = (8-0)/4 2 m/s 2 answer

10.The times for 4 cars to reach 100 km/h are shown below. Which car has the greatest acceleration? answer CarTime(s) A10.1 B8.3 C16.4 D12.9 Car B (shortest time to go from 0 – 100 km/h)

11. Describe the motion of the object represented by the speed – time graph below. Constant Speed answer time Speed o

12. The velocity – time graphs for two objects are shown below Which object has the larger acceleration. Object A – steepest slope answer A B time speed O

13. What is represented by the area under a speed- time graph? Distance travelled answer

14. State three effects of a force. Change of speed, shape and direction. answer

15. What is the unit of Force? Newtons (N) answer

16.Name an instrument which can be used to measure forces. Newton balance or spring balance. answer

17. What is a Scalar Quantity? Give examples. Scalar quantities can be described completely by their size or magnitude. e.g. Distance, time, mass and speed answer

18. What is a vector? Give examples. Vectors are quantities with a magnitude and a direction. e.g. Weight, displacement, acceleration and velocity. answer

19. What is the difference between speed and velocity. Velocity = displacement/time (vector) Speed = distance / time (scalar) answer

20. Which force always opposes the motion of an object? Friction answer

21.The forces on the object below are balanced. answer 50N F

22. The forces on an object are balanced. Describe the possible motion of the object. answer Stays at rest or moves with constant speed in a straight line.

23. An unbalanced force causes an object to accelerate. What will affect the size of the acceleration? answer The size of the unbalanced force and the mass of the object

24. A dog runs 300m south then turns and runs a further 400m east in a total time of 50s. What is the dog’s displacement from its starting position and its average velocity?. answer 300m 400m 300m 400m This is the resultant displacement, the magnitude can be calculated by Pythagoras. S = √(300 2 + 400 2 ) S = 500m We use SOH CAH TOA to work out angle x° which we need to give the direction. tan X = 400/300 x° = tan -1 (400/300) x° = 53.1°

25. A 4kg object has an acceleration of 5m/s 2. Find the unbalanced force acting on the object. answer F = m x a = 4 x 5 = 20N

26. Find the acceleration of the object shown below. answer 2m/s 2 10kg 20N

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