INDIAN SCHOOL AL WADI ALKABIR

DEPARTMENT OF SCIENCE, 2017 – 2018

CLASS: IX PHYSICS DATE:08.05.17

WS. NO.01 TOPIC : MOTION NAME:

  1. Give one example of a body whose average velocity is zero.
  2. A man is walking on a circular path of radius 100m. Calculate the Distance and displacement in (i) Half round (i) one complete round.
  3. Under what condition will the magnitude of the displacement be equal to the distance by an object? Give reason. ( BBQ –2 marks)
  4. Why is the motion of a circulating fan non uniform?
  5. Can the distance travelled by an object be smaller than the magnitude of its displacement? Explain with an example.
  6. A bridge is 500m long. A 100m long train crosses the bridge at a speed of 30m/s. Find the time taken by the train to cross it. ( Ans. 20s)
  7. Give two examples to explain that motion is relative.
  8. A frog hops from point A to point B along a straight line path and then turns and hops to point C. If A is at 7m from the origin, B at -2 m and C at 3m from the origin,

a)What is the distance travelled by the frog?

b)What is the magnitude and direction of displacement? ( BBQ- 3marks)

c)A car moves 100m due east and then 25m due west. (a) What is the distance covered by the car? (b) What is its displacement? (ans: 125m, 75m due east)

d)A person walks along the side of a square field of side 100m. What is the maximum magnitude of displacement of the person in any time interval?

  1. Mention the nature of a body if its displacement-time graph is a straight line. (BBQ 2,1mark)
  1. Describe the motion represented by the following displacement time graphs. (BBQ- 3marks)
  1. The following table show the distance travelled by three objects in every second.. (BBQ- 5marks)

TIME / DISTANCE TRAVELLED (in m)
OBJECT A / OBJECT B / OBJECT C
1ST SEC / 10 / 5 / 12
2ND SEC / 10 / 10 / 8
3RD SEC / 10 / 15 / 15
4TH SEC / 10 / 20 / 17
5TH SEC / 10 / 25 / 12

a)Classify the motion of the three objects as uniform or non-uniform motion.

b)Who has travelled the maximum and minimum distance in 4th sec?

c)Calculate the total distance travelled by A.

  1. A car moves through 20km at a speed of 40km/h and the next 20km at a speed of 60km/h. Calculate its average speed.
  2. A train is moving at a speed of 40km/h at 10.00a.m and at 50km/h at 10.02a.m. assuming that the train moves along a straight track and the acceleration is constant, find the value of the acceleration. (ans. 300 km/h2)
  3. Is it possible for a body to be in circular motion with constant velocity? Give reason. (2 marks)
  4. A cheetah can accelerate from rest at the rate of 4m/s2.

a)What will be the velocity attained by it in 10s?

b)How far it will travel in this

  1. A car covers 30km in 30 minutes and the next 30km in 40 minutes. Calculate the average speed for the entire journey. ( ans: 51.4 km/h) (3 marks)
  2. Differentiate between uniformly accelerated motion and uniform motion with example. ( BBQ- 3 marks)
  3. Derive graphically the three equations of accelerated motion. (5 Marks)
  4. The variation of a particle moving along a straight line in a certain time interval is shown below. What is the distance travelled during acceleration and the acceleration of the particle? ( B.Q) (2marks)

40

V (m/s)

0 5 10 15 20

T (s)

(ans- s = 400m a = - 2m/s2)

  1. Using the following data ,draw displacement time graph for a moving object and using the graph find the average velocity of the body for the first 4 seconds. ( B.Q) (HOTS) (3marks)

TIME (S) / 0 / 2 / 4 / 6 / 8 / 10 / 12
DISPLACEMENT(M) / 0 / 2 / 4 / 4 / 4 / 6 / 4

( v = 1m/s)

  1. A truck moving on a straight road with uniform acceleration. The following table gives the speed of the truck at different instants of time. ( B.Q 2012,5 marks )

speed(m/s) / 5 / 10 / 15 / 20 / 25 / 30
Time (s) / 0 / 10 / 20 / 30 / 40 / 50

Draw the speed time graph by choosing a convenient scale . Determine from it

a) the acceleration of the truck ( ans. 0.5m/s)

b) the distance travelled by the truck in 50s.

  1. Account for the following ( B.Q , 5 marks) (HOTS)

a) Name the quantity which is measured by the area occupied below the velocity – time graph.

b) An object is moving in a certain direction with an acceleration in the perpendicular direction.

c) Under what condition is the magnitude of average velocity of an object equal to the average speed?

d) An example of uniformly accelerated motion

e) A body is moving along a circular path of radius (R). What will be the distance and displacement of the body when it completes half revolution?

23.

A8( B.Q, 5 marks)

x

B

t

Give an example for uniform motion

Two cars A and B have their x-t graph as shown in the figure. Which has greater velocity and why?

What is the quantity measured by the area occupied below the velocity- time graph?

A body is moving with a velocity of 10m/s. If the motion is uniform, what will be the velocity after 10s?

24. (a) Can a body exist in a state of absolute rest? Explain with example.

(b) Draw a velocity-time graph for an object in uniform motion. Show that the area under the velocity-time graph gives the displacement of the object in the given time interval.(BBQ-5 marks)

25. Study the speed time graph of a body given below and answer the followingquestions.

(i)What type of motion is represented by OA, AB and BC ?

(ii) Find positive and negative accelerations of the body.

(iii)Find the distance travelled by the body from A to B. (BBQ-5marks)

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PREPARED BY ANU ANNIE MATHEWS