Laws of motion practice · Medium

When an elevator is moving downward with a increasing speed, the apparent weight of a body inside elevator

A projectile of mass m is thrown with a velocity v making an angle of ${45^0}$ with the horizontal. The change in momentum from departure to arrival along vertical direction, is

If the normal force is doubled, the coefficient of friction is

Which one of the following is not used to reduce friction

Which one of the following is not a force

A bird is sitting in a large closed cage which is placed on a spring balance. It records a weight of 25 N. The bird (mass m=0.5 kg) files upward in the cage with an acceleration of $2\;m/{s^2}$. The spring balance will now record a weight of

A lift is moving upwards with a uniform velocity v in which a block of mass m is lying. The frictional force offered by the block, when coefficient of the frictional is $\mu$, will be

Assertion : The two bodies of masses M and m (M > m) are allowed to fall from the same height if the air resistance for each be the same then both the bodies will reach the earth simultaneously.
Reason : For same air resistance, acceleration of both the bodies will be same.

A box is placed on an inclined plane and has to be pushed down. The angle of inclination is

When two surfaces are coated with a lubricant, then they

An automobile travelling with a speed of 60 km/h, can brake to stop within a distance of 20 m. If the car is going twice at fast,i.e. 120 km/h, the stopping distance will be

Two bodies having masses ${m_1}\,and\,{m_2}$ and velocities ${\mathrm{\vec u}_1}\,and\,{\mathrm{\vec u}_2}$ collide and form a composite system of ${m_1}{\mathrm{\vec v}_1} + {m_2}{\mathrm{\vec v}_2} = 0\left( {{m_1} \ne {m_2}} \right)$. The velocity of the composite system is

A car is moving along a straight horizontal road with a speed ${v_0}$. If the coefficient of friction between the tyres and the road is $\mu$, the shortest distance in which the car can be stopped is

A gun fires N bullets per second, each of mass m with velocity v. The force exerted by the bullets on the gun is

A constant force acts on a body of mass 0.9 kg at rest for 10s. If the body moves a distance of 250 m, the magnitude of the force is

The coefficient of limiting friction $\mu$ is defined as

In which of the following cases, net force acting on the
body is zero?

Newton's second and third laws of motion lead to the conservation of

A 10 kg stone is suspended with a rope of breaking strength 30 kg wt. The minimum time in which the stone can be raised through a height 10 m starting from rest is ( taking $g = 10\;N/kg)$

A body possesses kinetic energy x, moving on a rough horizontal surface, is stopped in a distance y. The friction force exerted on the body is

If two masses (M & m) are connected on a horizontal plane and a force is applied on the combination, then the tension T depends on

Which of the following statements is not true

The coefficient of static friction between two surfaces depends upon

Inertia is the property of a body linked to tendency of a body

Inertia of an object is directly dependent on

A particle rests on the top of a hemisphere of radius R. Find the smallest horizontal velocity that must be imparted to the particle if it is to leave the hemisphere without sliding down it

Statement-I: If the force varies with time in a complicated way then the net force is measured by the total change in momentum of the body.
Statement-II: Change in momentum and impulsive force are numerically equal.

One end of a string of length $l$ is connected to a particle of mass m and the other to a small peg on a smooth horizontal table. If the particle moves in a circle with speed v, the net force on the particle (directed towards the centre) is

The mass of a body measured by a physical balance in the lift at rest is found to be m. If the lift is going up with an acceleration a, its mass will be measured as

A ball is projected from ground with initial momentum p at an angle $\theta$. What is the magnitude of net change in linear momentum when it reaches at maximum height of journey?