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A circular disc with a groove along its diameter is
placed horizontally. A block of mass $1 kg$ is placed as shown. The coefficient of friction between the block and all surfaces of groove in contact is $μ = \frac{2}{5}$ .

The disc has an acceleration of $25 m s^{- 2}$ . Find the acceleration of the block with respect to disc,

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Important Questions on Laws of Motion

EASY

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A person is standing in an elevator. In which situation, he experiences weight loss ?

HARD

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

Two wooden blocks are moving on a smooth horizontal surface such that the block having mass $m$ remains stationary with respect to block of mass $M$ as shown in the figure below. The magnitude of the applied force $P$ is,

Question Image

EASY

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A block of mass

M

placed inside a box descends vertically with acceleration

a

. The block exerts a force equal to one-fourth of its weight on the floor of the box. The value of

a

will be

MEDIUM

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A car is negotiating a curved road of radius

R

. The road is banked at an angle

θ

. The coefficient of friction between the tyres of the car and the road is

μ_{s}

. The maximum safe velocity on this road is:

MEDIUM

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A boy is standing on a weighing machine inside a lift. When the lift goes upwards with acceleration

\frac{g}{4},

the machine shows the reading

50 kg .

wt. When the lift goes downward with acceleration

\frac{g}{4},

the reading of the machine in

kg

wt

. would be

EASY

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

Given in the figure are two blocks

A

and

B

of weight

20 N

and

100 N

, respectively. These are being pressed against a wall by a force

F

and kept in equilibrium as shown. If the coefficient of friction between the blocks is

0.1

and between block

B

and the wall is

0.15

, the frictional force applied by the wall on block

B

is:

MEDIUM

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

When a lift of mass

800 kg

is ascending with an acceleration of

5 m s^{- 2}

, the tension in its cable will be

______

take

(g = 10 m s^{- 2})

MEDIUM

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches

30 °

, the box starts to slip and slides

4.0 m

down the plank in

4.0 s

. The coefficients of static and kinetic friction between the box and the plank will be, respectively:
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HARD

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A girl drops an apple from the window of a train which is moving on a straight track with speed increasing with a constant rate. The trajectory of the falling apple as seen by the girl is

EASY

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A plumb line is suspended from a ceiling of a car moving with horizontal acceleration

a

. What will be the angle of inclination with vertical?

EASY

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

What is the minimum velocity with which a body of mass m must enter a vertical loop of radius

R

so that it can complete the loop?

HARD

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A particle is moving along the

x

-axis with its coordinate with time

t

given by

x (t) = 10 + 8 t - 3 t^{2} .

Another particle is moving along the

y

-axis with its coordinate as a function of time given by

y (t) = 5 - 8 t^{3} .

t = 1 s,

the speed of the second particle as measured in the frame of the first particle is given as

\sqrt{v} .

Then

v (i n m s^{- 1})

is ___________.

EASY

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A block kept on a rough inclined plane, as shown in the figure, remains at rest upto a maximum force

2 N

down the inclined plane. The maximum external force up the inclined plane that does not move the block is

10 N .

The coefficient of static friction between the block and the plane is: [Take

g = 10 m s^{- 2}

]

EASY

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A block

A

takes

2 s

to slide down a frictionless incline of

30 °

and length

l

, kept inside a lift going up with uniform velocity

v

. If the incline is changed to

45 °

, the time taken by the block, to slide down the incline, will be approximately:

MEDIUM

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

The potential energy of a particle of mass m at a distance r from a fixed point O is given by

V (r) = k r^{2} / 2

, where k is a positive constant of appropriate dimensions. This particle is moving in a circular orbit of radius R about the point O. If v is the speed of the particle and L is the magnitude of its angular momentum about O, which of the following statements is (are) true?

EASY

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A curved road of diameter

1.8 km

is banked so that no friction is required at a speed of

30 m s^{- 1}

. What is the banking angle?

MEDIUM

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A block

A

of mass

m_{1}

rests on a horizontal table. A light string connected to it passes over a frictionless pulley at the edge of table and from its other end another block

B

of mass

m_{2}

is suspended. The coefficient of kinetic friction between the block and the table is

μ_{k}

. When the block

B

is sliding on the table, the tension in string is:

EASY

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A man weighing

60 kg

is in a lift moving down with an acceleration of

1.8 {ms}^{- 2}

. The force exerted by the floor on him is?

MEDIUM

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

Two blocks

A

and

B

of masses

m_{A} = 1 k g

and

m_{B} = 3 k g

are kept on the table as shown in figure. The coefficients of friction between

A

and

B

0.2

and between

B

and the surface of the table is also

0.2 .

The maximum force

F

that can be applied on

B

horizontally, so that the block

A

does not slide over the block

B

is : [Take

g = 10 m / s^{2}

]

MEDIUM

Physics>Mechanics>Laws of Motion>Inertial and Non-inertial Frames of Reference

A rocket is fired vertically from the earth with an acceleration of 2g, where g is the gravitational acceleration. On an inclined plane inside the rocket, making an angle

θ

with the horizontal, a point object of mass m is kept. The minimum coefficient of friction

μ_{m i n}

between the mass and the inclined surface such that the mass does not move is:

Important Questions on Laws of Motion

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