Class 9 - foundation physics (Motion)Contact Number: 9667591930 / 8527521718

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1.

A particle moved from point A to point B, traveling some distance with speed $60{\mathrm{kmh}}^{-1}$. Then it moves back from B to A with speed 40 km/h. Find displacement, distance covered, average velocity and average speed for the entire journey.

2.

A particle moves in a circular path of radius 1m with uniform speed and takes 4 seconds to complete the circular path. Find distance, displacement, average speed and average velocity for-

1. A to B

2. A to C

3. A to D and

4. A to A.

3.

The displacement x of a particle is given by the equation $x=3{t}^{2}+4t+1$, where x is in metre and t is in seconds. find the instantaneous velocity of the particle at (i) t=1s; (ii) t=5s. Also, find the average velocity of the particle between =1s and t=5s.

4.

An object moving to the right has a decrease in velocity from 5.0 m/s to 1.0 m/s in 2.0 s. what is the average acceleration? What does your result mean?

5.

A car covers the first half of the distance between the two places at a speed of 40 km/h and the 2nd half at 60 km/h. What is the average speed of the car?

6.

The table below shows the distance (in cm), traveled by the objects A, B and C during each second.

1. Which object is moving with constant speed? Give a reason for your answer.

2. Which object is moving with constant acceleration? Give a reason.

3. Which object is moving with irregular acceleration?

7.

A body covers a distance of 20 m in the 7th second and 24 m in the 9th second. How much distance shall it cover in the 15th second?

8.

An automobile accelerates uniformly from rest to 25 m/s while traveling 100m. What is the acceleration of the automobile?

9.

A car is moving at a speed of 50 km/h. After two seconds, it is moving at 60 km/h. Calculate the acceleration of the car.

10.

A body with an initial velocity of 18 km/h accelerates uniformly at the rate of $9\mathrm{cm}{\mathrm{s}}^{-2}$ over a distance of 200 m. Calculate:

1. the acceleration in ${\mathrm{ms}}^{-2}$

2. its final velocity in ${\mathrm{ms}}^{-1}$

11.

The graph represents the velocity of a particle as a function of time.

1. What is the acceleration at 2.0 s?

2. What is the acceleration at 3.0 s?

3. What is the average acceleration between 0 and 5.0 s?

4. What is the average acceleration for the 8.0 s interval?

5. What is the displacement for the 8.0 s interval?

12.

A train starts from rest and accelerates uniformly at 100 m ${\mathrm{minutes}}^{-2}$ for 10 minutes. If then maintain a constant velocity for 20 minutes. The brakes are then applied and the train is uniformly retarded. Ti comes to rest in 5 minutes. Draw a velocity-time graph and use it to find:

1. the maximum velocity reached

2. the retardation in the last 5 minutes'

3. total distance traveled, and

4. the average velocity of the train

13.

A body is allowed to fall from a height of 98 m. Find the time taken by the body to hit the ground, its velocity before hitting the ground and the distance traveled by it in the last second of motion. (acc. due to gravity, g=$9.8\mathrm{m}/{\mathrm{s}}^{2}$).

14.

A stone is thrown vertically upwards with a speed of 80 m/s, simultaneously another stone is thrown vertically downward from a tower of height 400 m with a speed of 20 m/s. Find when and where the two stones meet. (take g=10 m/${\mathrm{s}}^{2}$).

15.

A ball is thrown at an angle of ${30}^{\xb0}$ with horizontal with a speed of $30{\mathrm{ms}}^{-1}$. Calculate maximum height, time of flight and horizontal range. (use g = 10 $\mathrm{m}/{\mathrm{s}}^{2}$).

16.

A body is projected at an angle of ${45}^{\xb0}$ if its horizontal range is 400 m, find corresponding maximum height.

17.

A particle projected with some velocity at an angle ${30}^{\xb0}$ with horizontal and another particle with the same speed but an angle of ${60}^{\xb0}$. Find the ratio of the range and maximum height.

18.

A body, when projected at angles of ${30}^{\xb0}\mathrm{and}{60}^{\xb0}$ the corresponding time of flights are 10 s and 20 s, respectively find horizontal range of projectile. (Use g=$10\mathrm{m}/{\mathrm{s}}^{2}$)

19.

A staircase contains 3 steps each 10 cm high and 20 cm wide. What should be the minimum horizontal velocity of a ball rolling off the uppermost plane so as to hit the lowest plane?

20.

A grindng wheel (radius 7.6 cm) is rotating at 1750 rpm.

1. What is the speed of a point on the outer edge of the wheel?

2. What is the centripetal acceleration of the point?

21.

Rishabh, a 20 kg child on his bicycle moving with a speed of 10 ${\mathrm{ms}}^{-1}$ takes a turn on a circular turning of radius 20 m. Calculate

1. the centripetal acceleration and

2. the centripetal force acting on Rishabh.

22.

A man standing on a road has to hold his umbrella at ${30}^{\xb0}$ with the vertical to keep the rain away. He throws the umbrella and starts running at 10 km/h. He finds that raindrops are hitting his head vertically. Find the speed of raindrops with respect to

1. road

2. the moving man

23.

A man swims at an angle $\mathrm{\theta}={120}^{\xb0}$ to the direction of water flow with a speed ${\mathrm{v}}_{\mathrm{MW}}=5\mathrm{km}/\mathrm{h}$ relative to water. If the speed of water ${\mathrm{v}}_{\mathrm{W}}=3\mathrm{km}/\mathrm{h}$, find the speed of the man.

24.

On a two lane road, car A is travelling with a speed of $36\mathrm{km}{\mathrm{h}}^{-1}$. Two cars B and C approach car A in opposite directions with a speed of $54\mathrm{km}{\mathrm{h}}^{-1}$ each. at a certain instant, when the distance AB is equal to AC, both being 1 km, B decides to overtake A before C does. What minimum acceleration of car B is required to avoid an accident?

25.

A cyclist travel from centre O of a circular park of radius 1 km and reaches point P. After cycling 1/4 th of the circumference along PQ, he returns to the centre of the park QO. If the total time taken is 10 minute, calculate

1. net displacement

2. average velocity and

3. average speed of the cyclist

26.

A bus moving with a velocity of 60 km/h is brought to rest in 20 seconds by applying brakes. Find its acceleration.

27.

A bullet moving with 10 m/s hits a wooden plank. The bullet is stopped when it penetrates the plank 20 cm deep. Calculate the retardation of the bullet.

28.

An athlete runs a distance of 1500 m in the following manner.

1. Starting from rest, he accelerates himself uniformly at $2\mathrm{m}/{\mathrm{s}}^{2}$ till he covers a distance of 900 m.

2. He, then runs the remaining distance of 600 m at the uniform speed developed. Calculate the time taken by the athlete to cover the two parts of the distance covered.

29.

A car starts moving rectilinearly, first with acceleration $\mathrm{a}=5\mathrm{m}/{\mathrm{s}}^{2}$ (the initial velocity is equal to zero), uniformly, and finally decelerating at the same rate $\mathrm{\alpha}$ comes to a stop. The total time of motion equals $\mathrm{\tau}=25\mathrm{s}$. The average velocity during that time is equal to <v> = 72 km/h. How long does the car move uniformly?

30.

A train moves from one station to another in two hours time. It s speed time-graph during the motion is shown in figure.

1. Determine the maximum acceleration during the journey.

2. Also calculate the distance covered during the time interval from 0.75 hour to 1 hour.

31.

A body covers 12 m in 2nd and 20 m in 4th second. How much distance will it cover in 4 second after the 5th second?

32.

A swimmer crosses 200 m wide channel with straight bank and return in 10 minute at a point 300 m below the starting point (downstream). Find the magnitude and the direction of the velocity of the swimmer relative to the bank if he heads towards the bank to the channel all the time at right angles.

33.

An aeroplane flying horizontally with a speed of 49 m/s releases a bomb at a height of 490 m. Find the time taken by the bomb to reach the ground and also the magnitude and the direction of velocity with which it strikes the ground.

34.

a body of mass 2kg lying on a smooth surface is attached to a string 3m long and then whirled round in a horizontal cirlce making 60 revolution per minute. Find

1. the angular velocity

2. the linear velocity

3. the centripetal acceleration and

4. the tension in the string

35.

What does the speedometer record - the average speed or instantaneous speed?

36.

Can a body moving with a uniform velocity be in equilibrium?

37.

Two particles A and B are moving along the same straight line with B ahead of A. Velocity remaining unchanged, what would be the effect on the magnitude of relative velocity, if A is ahead of B?

38.

Under what condition the average velocity of a body is equal to its instantaneous velocity?

39.

When the magnitude of average velocity is same as that of average speed?

40.

Can a particle has varying speed but a constant velocity?

41.

what is the acceleration of a paticle moving with uniform velocity?

42.

Under what condition will the distance and displacement of a moving object have the same magnitude?

43.

What does the slope of position and time graph represents for uniform motion?

44.

what does slope of v-t graph represent?

45.

A ball is thrown straight up. What is its velocity and acceleration at the top?

46.

A stone relaesed with zero velocity from the top of the tower reaches the ground in 4 second. What is the approximate height of the tower?

47.

A stone is thrown upwards with a velocity v from the top of a tower. It reaches the ground with a velocity 3v. what is the height of the tower?

48.

A body is projected vertically upwards with the velocity of 96 ft/s. What will the total time for which the body remains in air? Assume, acceleration due to gravity, $\mathrm{g}=32{\mathrm{fts}}^{-2}$.

49.

The velocity of a body moving with a uniform acceleration of $2{\mathrm{ms}}^{-2}\mathrm{is}10{\mathrm{ms}}^{-1}$. What is its velocity after an interval of 4 second?

50.

A motor car moving with a uniform velocity of $20{\mathrm{ms}}^{-1}$ comes to a stop, on the application of brakes, after travelling a distance of 10 m. What is its acceleration?

51.

A wooden block of mass 10 g is dropped from the top of a cliff 100 m high. Simultaneously, a bullet of mass 10 g is fired from the foot of the cliff upwards with a velocity $100{\mathrm{ms}}^{-1.}$

After what time, bullet and the block meet?

52.

Draw the position time graph for particle moving with positive and negative velocities.

53.

A car travels half the distance with constant velocity $30\mathrm{km}{\mathrm{h}}^{-1}$ and another half with a constant velocity of $40\mathrm{km}{\mathrm{h}}^{-1}$. What is the average velocity of the car?

54.

For a particle in one dimensional motion, the instantaneous speed is always equal to the magnitude of instantaneous velocity. Why?

55.

What type of motions are represented by the following velocity- time graph?

1.

2.

3.

4.

56.

a circular track has a circumference of 3140 m with AB as one of its diameter. Q scooterist moves from A to B along the circulat path with a uniform speed of 10 m/s. find

1. Distance covered by the scooterist,

2. displacement of the sccoterist

3. time taken by the scooterist in reaching from A to B.

57.

An object has moved through a distance. Can it have zero displacement? If yes, support your answer with an example.

58.

A farmer moves along the boundary of a square field of side 10 m in 40 s. What will be the magnitude of displacement of the farmer at the end of 2 minutes 20 seconds form his initial position?

59.

Which of the following is true for displacement?

1. It cannot be zero

2. Its magnitude is greater than the distance travelled by the onject.

60.

Distinguish between speed and velocity.

61.

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

62.

What does the odometer of an automobile measures?

63.

What does the path of an object look like when it is in uniform motion?

64.

During an experiment, a signal from a spaceship reached the ground station in five minutes. What was the distance of the spaceship from the ground station? The signal travels at the speed of light, that is, $3\times {10}^{8}{\mathrm{ms}}^{-1}$

65.

When will you say a body is in

1. uniform acceleration

2. non-uniform acceleration?

66.

A bus decreases its speed from $80{\mathrm{kmh}}^{-1}\mathrm{to}60{\mathrm{kmh}}^{-1}$ in 5s. Find the acceleration of the bus.

67.

A train starting from the railway station and moving with a uniform acceleration attains a speed of $40{\mathrm{kmh}}^{-1}$ in 10 minutes. Find its acceleration.

68.

What is the nature of the distance time graph is a straight line parallel to the time axis?

69.

What can you say about the motion of an object whose distance time graph is a straight line parallel to the time axis?

70.

What can you say about the motion of an object if its speed time graph is a straight line parallel to th etime axis?

71.

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

72.

A bus starting from rest moves with a uniform acceleration of $0.1{\mathrm{ms}}^{-2}$ for 2 minutes. Find

1. the speed acquired,

2. the distance travelled

73.

a train is travelling at a speed of $90km{h}^{-1}$. Brakes applied so as to produce a uniform acceleration of $0.5{\mathrm{ms}}^{-2}$. Find how far the train will go before it is brought ti rest?

74.

A trolly while going down an inclined plane has an acceleration of $2{\mathrm{cms}}^{-2}$. What will be its velocity 3 s after the start?

75.

A racing car has a uniform accleration of $4{\mathrm{ms}}^{-2}$. What distance will it cover in 10 s after start?

76.

A stone is thrown in a vertically upward direction with a velocity of $5{\mathrm{ms}}^{-1}$. If the accleration of the stone during its motion is $10{\mathrm{ms}}^{-2}$ in the downward direction, what will be the height attained by the stone and how much time will it take to reach there?

77.

An athlete completes one round of a circular track of diameter 200 m in 40 s. what will be the distance covered and the displacement at the end of 2 minutes 20 s?

78.

Joseph jogs from one end A to B of a straight 300 m road in 2 minutes 30 seconds and then turns around and jogs 100 m back to point c in another 1 minute. What are Joseph's average speeds and velocities in jogging (a) from A to B and (b) form A to C?

79.

Abdul, while driving to school, computes the average speedfor his trip to be 20 km ${\mathrm{h}}^{-1}$. On his return trip along ther same route, there is less traffic and the average speed is 30 km ${\mathrm{h}}^{-1}$. What is the average speed of the Abdul's trip?

80.

A motorboat starting from rest on a lake accelerates in a straight line at a constant rate of $3.0\mathrm{m}{\mathrm{s}}^{-2}$ for 8.0 s. How far does the boat travel during this time?

81.

A driver of a car travelling at $52\mathrm{km}{\mathrm{h}}^{-1}$ applies the brakes and accelerates uniformly in the opposite direction. The car stops in 5s. Another driver going at $34\mathrm{km}{\mathrm{h}}^{-1}$ in another car applies his brakes slowly and stops in 10s. On the same graph paper, plot the speed versus time graphs for the two cars. Which of the two cars travelled farther after the brakes were applied?

82.

Fig. shows the distance time graph of three objects A, B, and C. Study the graph and answer the following questions.

1. which of the three is travelling the fastest?

2. Are all three ever at the same point on the road?

3. How far has C travelled when B passes A?

4. How far has B travelled by the time it passes C?

83.

A ball gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of $10{\mathrm{ms}}^{-2}$, with what velocity will it strike the ground? After what time will it strike the ground?

84.

The speed time graph for a car is shown in fig.

1. Find how far does the car travel in the first 4 seconds. Shade the area on the graoph that represents the distance travelled by the car during the period.

2. Which part of the graph represents uniform motion of the car?

85.

State which of the following situations are possible and give an example for each of these:

1. an object with a constant acceleration but with zero velocity.

2. an object moving in a certain direction with an acceleration in the perpendicular direction.

86.

An artificial satellite is moving in a circular orbit of radius 42250 km. Calculate its speed if its takes 24 hours to revolve around the earth.

87.

The displacemnt of a moving object in a given interval of time is zero. Would the distance travelled by the object also be zero? Justify your answer.

88.

A girl walk along a straight path to drop a letter in the letter box and comes back to their initial position. Her displacement - time graph is shown in fig. plot a velocity time graph for the same.