Tuesday, June 19, 2012
Thursday, June 14, 2012
Question and Answer on Motion
Very Short Answer Type Question
1. Is the displacement is scalar quantity?
2. State whether distance is a scalar or a vector quantity?
3. Change the speed of 6 m/s into km/h.
4. What name is given to the speed in a specified direction?
5. Give two examples of bodies having non-uniform motion.
6. Name the physical quantity obtained by diving ‘Distance travelled’ by ‘Time taken’ to travel that distance.
7. What do the following measures in a car?
(a) Speedometer (b) Odometer
8. Name the physical quantity which gives us an idea of how slow or fast a body is moving.
9. Under what conditions can a body travels a certain distance and yet its resultant displacement be zero?
10. In addition to speed, what else should we know to predict the position of a moving body?
11. When is a body said to have uniform velocity?
12. Under which condition is the magnetic of average velocity equal to average speed?
13. Which of the two can be zero under certain conditions: average speed of a moving body or average velocity of a moving body?
14. Give one example of a situation in which a body has a certain average speed but its average velocity is zero.
15. What is the acceleration of a body moving with uniform velocity?
16. What is the other name of negative acceleration?
17. Name the physical quantity whose SI unit is:
(a) m/s (b) m/s2
18. What type of motion is exhibited by a freely falling body?
19. What is the SI unit of retardation?
20. Fill in the blanks with suitable words:
(a) Displacement is a …………. Quantity whereas distance is a................. Quantity.
(b) The physical quantity which gives both, the speed and direction of motion of a body is called it’s ………. .
(c) A motorcycle has a steady ………….. of 3 m/s2. This means that every ………. It’s ………… increased by ………….
(d) Velocity is the rate of change of ………... It is measured in …………..
(e) Acceleration is the rate of change of ………. It is measured in ………..
21. What type of motion, uniform or non-uniform, is exhibited by freely falling body? Give reason for your answer.
23. Bus X travels a distance 360 km in 5 hours whereas bus Y travels a distance of 476 km in 7 hours. Which bus travels faster?
24. Arrange the following speed in increasing order:
(i) an athlete running with a speed of 10 m/s.
(ii) a bicycle moving with a speed of 200 m/s.
(iii) a scooter moving with a speed of 30 km/h.
25. (a) Write the formula for acceleration. Give the meaning of each symbol which occurs in it.
(b) A train starting from railway station attains a speed of 21m/s in one minute. Find its acceleration.
26. (a) What terms is used to denote the change of velocity with time?
(b) Give one word which means the same as ‘moving with a negative acceleration’.
(c) The displacement of a moving object in given interval of time is zero. Would the distance traveled by the object also be zero? Give reason for your answer.
27. A snail covers a distance of 100 meters in 50 hours. Calculate the average speed of snail in km/h.
28. A tortoise moves a distance of 100 meters in 15 minutes. What is the average speed of tortoise in km/h?
29. If a sprinter runs a distance of 100 meters in 9.83 seconds, calculate his average speed in km/h.
30. A motorcycle drives from place A to B with a uniform speed of 30 km/h and returns from place B to A with a uniform speed of 20 km/h. What is its acceleration?
31. A motorcyclist starts from rest and reaches a speed of 6 m/s after traveling with uniform acceleration for 3 s. What is his acceleration?
32. An air craft traveling at 600 km/h accelerates steadily at 10 km/h per second. Taking the speed of sound as 1100 km/h at the aircraft’s altitude, how long will it take to reach the ‘sound barrier’?
33. If a bus traveling at a speed of 20 m/s is subjected to steady deceleration of 5 m/s2, how long will it take to come to rest?
Answers
1. No it is a vector quantity.
2. Distance is a scalar quantity.
3. 21.6 km/h
4. Velocity.
5. Movement of a car in crowded road and racing bike.
6. Speed
7. (a) Measures Speed (b) Measures Distance traveled
8. Speed
9. When the body comes back to its starting point.
10. Direction of speed
11. When a body travels same distance at same interval of time.
12. When the body moves along a straight line path.
13. Average velocity.
14. When a body have same initial position and final position
15. Zero (0)
16. Retardation
17. (a) Speed (b) Acceleration
18. Non Uniform Velocity
19. m/s2
20.
(a) Vector; Scalar
(b) Velocity
(c) Acceleration; Second; Speed (or Velocity); 3 m/s
(d) Displacement; m/s
(e) Velocity; m/s2
21. Non uniform motion because when it comes near the earth surface due to high gravitation force it changes its speed.
22. Speed is a scalar quantity because it does not have direction.
23. Speed bus X = 72 km/h; Speed of bus Y= 68 km/h; so bus X travels faster.
24. 200 m/min <30 km/h <10 m/s
25.
(a) a = v-u/t
Where,
a is the acceleration of the body.
v is the final velocity of the body.
u is the initial velocity of the body.
t is the time taken by the body.
(b) 0.35 m/s2
26. (a) Acceleration
(b) Retardation
(c) No, because distance is a scalar quantity having the magnitude only. It has no specified direction.
27. 0.002 km/h
28. 0.04 km/h
29. 36.62 km/h
30. 24 km/h
31. 2 m/s2
32. 50 s
33. 4 s
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