Laws of motion practice · Mixed difficulty

A block is lying on the horizontal frictionless surface. One end of a uniform rope is fixed to the block which is pulled in the horizontal direction by applying a force $F$ at the other end. If the mass of the rope is half the mass of the block, the tension in the middle of the rope will be

Assertion: A man in a closed cabin falling freely experience weightlessness.
Reason: Inertial and gravitational mass have equivalence.

A parachutist is in free fall before opening her parachute. The net force on her has a magnitude $F$ and is directed downwards. This net force is somewhat less than, her weight $w$ because of air resistance. Then, she opens her parachute. At the instant after her parachute fully inflates, the net force on her would be

The average resisting force that must act on a $5 \mathrm{~kg}$ mass to reduce its speed from $65$ to $15 \mathrm{~ms}^{-1}$ in $2 \mathrm{~s}$ is

Which of the following statement is NOT true for kinetic friction?

Statement-1: A man starts walking towards west. Friction force on him acts towards east.
Statement-2 : Friction opposes relative motion.

Motion of the particle is non uniform when

A shell initially at rest explodes into two pieces of equal mass, then the two pieces will

A body of weight 64 N is pushed with just enough force to start it moving across a horizontal floor and the same force continues to act afterwards. If the coefficients of static and dynamic friction are 0.6 and 0.4 respectively, the acceleration of the body will be (Acceleration due to gravity =g)

Statement-I: The apparent weight of a body in an elevator moving with some downward acceleration is less than the actual weight of body.
Statement-II: The part of the weight is spent in producing downward acceleration, when body is in elevator.

Statement-I: When the lift moves with uniform velocity the man in the lift will feel weightlessness.
Statement-II: In downward accelerated motion of lift, apparent weight of a body increases.

Shock absorbers are used in vehicles to reduce the magnitude of

Assertion : Impulse of force and momentum are same physical quantities.
Reason : Both quantities have same unit.

It is easier to draw up a wooden block along an inclined plane than to haul it vertically, principally because

The position vector of a particle related to time $t$ is given by $\vec{r}=\left(5 t^2 \hat{i}+3 t \hat{j}+4 \hat{k}\right)$. The direction of net force experienced by the particle is

A block can slide on a smooth inclined plane of inclination $\mathrm{\theta }$ kept on the floor of a lift. When the lift is descending with a retardation a, the acceleration of the block relative to the incline is

A body takes time t to reach the bottom of an inclined plane of angle $\theta$ with the horizontal. If the plane is made rough, time taken now is 2t. The coefficient of the friction of the rough surface is

A ball moves in a frictionless inclined table without slipping. The work done by the table surface on the ball is

A body of mass $0.1 {~kg}$ attains a velocity of ${1 0}$ ${ms}^{-1}$ in $0.1 {~s}$. The force acting on the body is

If the net external force on a body is ...X..., its acceleration is zero. Acceleration can be ...Y... only, if there is a net external force on the body. Here, X and Y refer to

Two blocks of masses $M=3 \mathrm{~kg}$ and $\mathrm{m}=2 \mathrm{~kg}$, are in contact on a horizontal table. A constant horizontal force $\mathrm{F}=5 \mathrm{~N}$ is applied to block $\mathrm{M}$ as shown. There is a constant frictional force of $2 \mathrm{~N}$ between the table and the block $\mathrm{m}$ but no frictional force between the table and the first block $M$, then the acceleration of the two blocks is

Starting from rest, the time taken by a body sliding down on a rough inclined plane at ${45^0}$ with the horizontal is twice the time taken to travel on a smooth plane of same inclination and same distance. Then the coefficient of kinetic friction is

What is the working principle of a jet engine?

Statement-I: The work done in bringing a body down from the top to the base along a frictionless incline plane is the same as the work done in bringing it down the vertical side
Statement-II: The gravitational force on the body along the inclined plane is the same as that along the vertical side.

Impulse of a force is equal to the change in-

A 60 kg man stands on a spring scale in the lift. At some instant he finds, scale reading has changed from 60 kg to 50 kg for a while and then comes back to the original mark. What should we conclude

An open carriage in a goods train is moving with a uniform velocity of 10 $\;\mathrm{m}{\mathrm{s}^{ - 1}}$. If the rain adds water with zero velocity at the rate of 5 $\mathrm{kg}{\mathrm{s}^{ - 1}}$, then the additional force applied by the engine to maintain the same velocity of the train is

A particle of mass 10g is moving with a velocity $2\hat i + \hat j + 3\hat k$ (cm/s) Magnitude of its linear momentum is

Statement-I: The velocity of a body at the bottom of an incline plane of given height is more when it slides down the plane, compared to, when it rolling down the same plane.
Statement-II: In rolling down a body acquires both, kinetic energy of translation and rotation.

Statement-1: For a body resting on level ground normal reaction and weight form Newton's $3^{\text {rd}}$ law action-reaction pair.
Statement-2: Action-reaction pair of Newton's $3^{\text {rd}}$ law are equal and opposite.