For distance ∝ ( time ) 3 we can use equations of motion. Comment.

When distance ∝ ( time ) 3 , we cannot use the equation of motion because in this case, as the acceleration is not constant. If distance ∝ ( time ) 2 , the body has uniform acceleration and the second equation of motion can be used.

For distance ∝ ( time ) 2 , we can use equations of motion. Comment.

The second equation of motion, s = u t + 1 2 a t 2 , if the initial velocity u = 0 , then s α t 2 . Therefore, when distance ∝ ( time ) 2 , the body has uniform acceleration and the equations of motion can be used.

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What is the correct transformation of the sentence: 'No sooner did he reach the station than the train left.'?

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Important Questions on Gravitation

EASY

Physics>Mechanics>Gravitation>Earth Satellites

The stream of a river is flowing with a speed of

2 k m h^{- 1}

. A swimmer can swim at a speed of

4 km h^{- 1}

. The direction of the swimmer with respect to the flow of the river, to cross the river straight, is

EASY

Physics>Mechanics>Gravitation>Earth Satellites

The correct thermodynamic conditions for the spontaneous reaction at all temperatures is:

MEDIUM

Physics>Mechanics>Gravitation>Earth Satellites

A bullet loses

{(\frac{1}{n})}^{th}

of its velocity passing through one plank. Considering uniform retardation, the number of such planks that are required to stop the bullet can be:

MEDIUM

Physics>Mechanics>Gravitation>Earth Satellites

For $distance \propto (time)^{3}$ we can use equations of motion. Comment.

EASY

Physics>Mechanics>Gravitation>Earth Satellites

A person sitting in an open car moving at constant velocity throws a ball vertically up into air. The ball falls

MEDIUM

Physics>Mechanics>Gravitation>Earth Satellites

Figure given shows the

x - t

plot of a particle executing one-dimensional simple harmonic motion. Give the signs of position, velocity and acceleration variables of the particle at

t = 0.3 s, 1.2 s, - 1.2 s

EASY

Physics>Mechanics>Gravitation>Earth Satellites

A ball is projected vertically upwards with a speed of

50 m s^{- 1}

. Find the time required to reach the maximum height.

MEDIUM

Physics>Mechanics>Gravitation>Earth Satellites

For $distance \propto (time)^{2}$ , we can use equations of motion. Comment.

EASY

Physics>Mechanics>Gravitation>Earth Satellites

A car moving along a straight highway with a speed of

126 k m h^{- 1}

is brought to a stop within a distance of

200 m

. What is the retardation of the car (assumed uniform), and how long does it take for the car to stop?

MEDIUM

Physics>Mechanics>Gravitation>Earth Satellites

A three-wheeler starts from rest, accelerates uniformly with

1 m s^{- 2}

on a straight road for

10 s

, and then moves with uniform velocity. Plot the distance covered by the vehicle during the

n

th second

(n = 1,2, 3 \dots .)

versus

n

. What do you expect this plot to be during accelerated motion: a straight line or a parabola?

MEDIUM

Physics>Mechanics>Gravitation>Earth Satellites

A boy standing on a stationary lift (open from above) throws a ball upwards with the maximum initial speed he can, equal to

49 m / s

. How much time does the ball take to return to his hands? If the lift starts moving up with a uniform speed of

5 m / s

and the boy again throws the ball up with the maximum speed he can, how long does the ball take to return to his hands?

MEDIUM

Physics>Mechanics>Gravitation>Earth Satellites

If the velocity of a car is increased by 20%, then the minimum distance in which it can be stopped increase by

MEDIUM

Physics>Mechanics>Gravitation>Earth Satellites

Read the statement below carefully and state with reasons and examples, if it is true or false:

A particle in one-dimensional motion with zero speed at an instant may have non-zero acceleration at that instant.

EASY

Physics>Mechanics>Gravitation>Earth Satellites

A chain of length

L

and of mass

m

is placed upon a smooth surface. The length of

B A

L - b

. Now, the chain is released and it slides down. Calculate the speed of the chain when its end reaches

B

EASY

Physics>Mechanics>Gravitation>Earth Satellites

A stone is thrown vertically upwards with a speed of

28 m s^{- 1}

. Find its velocity one second before it reaches the maximum height.

MEDIUM

Physics>Mechanics>Gravitation>Earth Satellites

A player throws a ball upwards with an initial speed of

29.4 m s^{- 1}

.
(a) What is the direction of acceleration during the upward motion of the ball?
(b) What are the velocity and acceleration of the ball at the highest point of its motion?
(c) Choose the

x = 0 m

and

t = 0 s

to be the location and time of the ball at it’s highest point, vertically downward direction to be the positive direction of the x-axis, and give the signs of position, velocity and acceleration of the ball during its upward, and downward motion.
(d) To what height does the ball rise and after how long does the ball return to the player’s hands? (Take

g = 9.8 m s^{- 2}

and neglect air resistance).

EASY

Physics>Mechanics>Gravitation>Earth Satellites

The speed-time graph of a particle moving along a fixed direction is shown in Figure. Obtain the distance traversed by the particle between

(a) $t = 0 s$ to $10 s,$

(b) $t = 2 s$ to $6 s$

Question Image
What is the average speed of the particle over the intervals in (a) and (b)?

EASY

Physics>Mechanics>Gravitation>Earth Satellites

The acceleration due to gravity on the planet A is

9

times the acceleration due to gravity on planet B. A man jumps to height of

2 m

on the surface of

A .

What is the height of jump by the same person on the planet

B

HARD

Physics>Mechanics>Gravitation>Earth Satellites

Two stones are thrown up simultaneously from the edge of a cliff

200 m

high with initial speeds of

15 m s^{- 1}

and

30 m s^{- 1}

. Verify that the graph shown in Figure correctly represents the time variation of the relative position of the second stone with respect to the first. Neglect air resistance and assume that the stones do not rebound after hitting the ground. Take

g = 10 m s^{- 2}

. Give the equations for the linear and curved parts of the plot.
Question Image

EASY

Physics>Mechanics>Gravitation>Earth Satellites

Give example where (a) the velocity of a particle is zero but its acceleration is not zero (b) the velocity is opposite in direction to the acceleration, (c) the velocity is perpendicular to the acceleration.

What is the correct transformation of the sentence: 'No sooner did he reach the station than the train left.'?

Important Questions on Gravitation

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