Laws of motion practice · Mixed difficulty

A 50g bullet moving with a velocity of $10\mathrm{\;m}{\mathrm{s}^{ - 1}}$ gets embeded into a 950g stationary body. The loss in KE of the system will be

If a coin is dropped in a lift it takes $t_1$ time to reach the floor and takes $t_2$ time when lift is moving up with constant acceleration, then which one of the following relation is correct?

In which of the following cases forces may not be required to keep the

A metre scale is moving with uniform velocity. This implies

In relativity which is constant between two frames of reference

A disc rotates about its axis of symmetry in a horizontal plane at a steady rate of 3.5 revolutions per second. A coin placed at a distance of 1.25 cm from the axis of rotation remains at rest on the disc. The coefficient of friction between the coin and the disc is $\left( {g = 10m/{s^2}} \right)$

Statement I: Improper banking of roads causes wear and tear of tyres.
Statement II: The necessary centripetal force in that event is provided by friction between the tyres and roads.

A block compartment containing gas is moving with some acceleration in horizontal direction. Neglect effect of gravity. Then the pressure in the compartment is

A block of mass 1 kg lies on a horizontal surface in a truck, the coefficient of static friction between the block and the surface is 0.6. The force of friction on the block if the acceleration of the truck is $5\,m{s^{ - 2}}$ is: $\left( {g = 10m/{s^2}} \right)$

Assertion : On a rainy day, it is difficult to drive a car or bus at high speed.
Reason : The value of coefficient of friction is lowered due
to wetting of the surface.

A constant horizontal force of 20 N acts on a body on a smooth horizontal plane. The body starts from rest and is observed to move 20 m in two seconds. The mass of the body is

An electric fan is placed on a stationary boat
and air is blown with it on the sail of the boat.
Which of the following statements is correct?

A rocket with a lift-off mass $3.5 \times 10^4 \mathrm{~kg}$ is blast upward with an initial acceleration of $10 \mathrm{~ms}^{-2}$. Then, the initial thrust of the blast 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.

You are pushing a wooden crate across the floor at a constant speed. You decide to change the orientation of crate such that area of contact with floor become half. In the new orientation, to push the same crate across the same floor with the same constant speed, the force that you apply must be about as the force required before you changed the crate's orientation.

The angle of inclination of an inclined plane is $30^\circ$ coefficient of friction between 12 kg body on it and its surface is 0.3. The acceleration of the body down the plane in $\left( {g = 10\,m/{s^2}} \right)$

If a person with a spring balance and a body hanging from it goes up and up in an aeroplane, then the reading of the weight of the body as indicated by the spring balance will

What should be the coefficient of friction between the tyres and the road, when a car travelling at 60 $\mathrm{km\;}{\mathrm{h}^{ - 1}}$ makes a level turn of radius 40 m?

Frictional force that opposes relative motion between surfaces in contact is called ...X... and denoted by ...Y.... Here, X and Y refer to

A bike of mass 300 kg taking turn on a banked road of radius 100 m and banking angle $37^\circ.$ If coefficient of static friction is 0.25. Then the maximum speed with which car can negotiate the turn safely. $\left(g=10 \mathrm{~m} / \mathrm{s}^2\right)$

Choose the wrong statement

Five forces inclined at an angle of $72^{\circ}$ w.r.t. each other act on a particle of mass $m$ placed at the origin. Four forces are of magnitude $F_1$ and one has a magnitude $F_2$. Find the resultant acceleration of the particle.

In case of uniform circular motion which of the following physical quantity do not remain constant

Sand is being dropped on a conveyor belt at the rate of M kg/s . The force necessary to keep the belt moving with a constant velocity of V m/s will be [newton]

A machine gun fires a bullet of mass 46 g with a velocity 1050 m/s. The man holding it can exert a maximum force 144 N on the gun. How many bullets can he fire per second at the most?

Two balls each of mass 1 kg moving in opposite directions with speed 15 m/s collides and rebounds with the same speed. The magnitude of impulse imparted to each ball due to other is

The momentum of a particle is $\mathrm{\vec P}\,2cos\,\mathrm{t\hat i} + 2\mathrm{sint}\,\mathrm{\hat j}$. What is the angle between the force $\mathrm{\vec F}$ acting on the particle and the momentum $\mathrm{\vec P}$

A constant force (F) is applied on a stationary particle of mass $'m'$ . The velocity attained by the particle in a certain displacement will be proportional to

A ball hits a vertical wall horizontally at 10 m/s bounces back at 10 m/s

A 100 kg car is moving with a maximum velocity of 9 m/s across a circular track of radius 30 m. The maximum force of friction between the road and the car is