MEDIUM

Earn 100

Two observers measure normal reaction on a body where observer $O_{1}$ is in a lift going upwards and $O_{2}$ is on the ground. Then,

80.95% studentsanswered this correctly

Important Questions on Laws of Motion

EASY

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

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

HARD

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

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>Newton’s Laws of Motion

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>Newton’s Laws of Motion

A stream of water flowing horizontally with a speed of

15 m s^{- 1}

gushes out of a tube of cross-sectional area

10^{- 2} m^{2}

and hits a vertical wall nearby. The force exerted on the wall by the impact of water (assuming it does not rebound) is

MEDIUM

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

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

MEDIUM

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

A mass of

10 kg

is suspended vertically by a rope from the roof. When a horizontal force is applied on the rope at some point, the rope deviated at an angle of

45 °

at the roof point. If the suspended mass is at equilibrium, the magnitude of the force applied is

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

MEDIUM

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

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>Newton’s Laws of Motion

Two masses

m_{1} = 5 kg

and

m_{2} = 10 kg

, connected by an inextensible string over a frictionless pulley, are moving as shown in the figure. The coefficient of friction of horizontal surface is

0.15

. The minimum weight

m

that should be put on top of

m_{2}

to stop the motion is:

Question Image

HARD

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

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>Newton’s Laws of Motion

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?

MEDIUM

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

A rod of weight

W

is supported by two parallel knife edges

A

and

B

and is in equilibrium in a horizontal position. The knives are at a distance

d

from each other. The centre of mass of the rod is at distance

x

from

A

. the normal reaction on

A

is:

HARD

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

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 ___________.

MEDIUM

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

An elevator of mass

m

is connected to a rope which pulls the elevator up with a maximum acceleration equal to

a

. If the maximum bearable tension in the rope is

T

, then for a safe journey the minimum diameter of the rope is [

g

= acceleration due to gravity]

EASY

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

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:

HARD

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

On heating water, bubbles being formed at the bottom of the vessel detatch and rise. Take the bubbles to be spheres of radius R and making a circular contact of radius r with the bottom of the vessel. If r << R, and the surface tension of water is T, value of r just before bubbles detatch is :
(density of water is

ρ_{w}

)

EASY

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

A particle moving with velocity $\vec{V}$ is acted by three forces shown by the vector triangle $P Q R$ . The velocity of the particle will
Question Image

MEDIUM

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

A block of mass

10 k g

is in contact against the inner wall of a hollow cylindrical drum of radius

1 m

. The coefficient of friction between the block and the inner wall of the cylinder is

0.1

. The minimum angular velocity needed for the cylinder to keep the block stationary when the cylinder is vertical and rotating about its axis will be

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

EASY

Physics>Mechanics>Laws of Motion>Newton’s Laws of Motion

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>Newton’s Laws of Motion

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>Newton’s Laws of Motion

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:

Two observers measure normal reaction on a body where observer O1 is in a lift going upwards and O2 is on the ground. Then,

Important Questions on Laws of Motion

Learn and Prepare for any exam you want !

Two observers measure normal reaction on a body where observer $O_{1}$ is in a lift going upwards and $O_{2}$ is on the ground. Then,