Overview

Three objects A, B and C are kept in a straight line on a frictionless horizontal surface. The masses of A, B and C are m, 2m and 2m respectively. A moves towards B with a speed of 9m/s and makes an elastic collision with it. Thereafter B makes a completely inelastic collision with C. All motions occur along same straight line. The final speed of C is:

A force F = (40î + 10?)N acts on a body of mass 5 kg. If the body starts from rest, its position vector r at time t = 10s, will be :

Two billiard balls of equal mass 30g strike a rigid wall with same speed of 108 kmph (as shown) but at different angles. If the balls get reflected with the same speed then the ratio of the magnitude of impulses imparted to ball 'a' and ball 'b' by the wall along 'X' direction is :
(Diagram shows ball 'a' hitting the wall perpendicularly along the x-axis and ball 'b' hitting the wall at a 45° angle to the x-axis.)

An inclined plane in bent in such a way that the vertical cross-section is given by y  where y is in vertical and x in horizontal direction. If the upper surface of this curved plane is rough with coefficient of friction = 0.5, the maximum height in cm at with a stationary block with not skip downward is ____________cm.

The coefficient of static friction between a wooden block of mass 0.5kg and a vertical rough wall is 0.2. The magnitude of horizontal force that should be applied on the block to keep it adhere to the wall be__________ N.

A person standing on a balance inside a stationary lift measures 60 kg. The weight of that person if the lift descends with uniform downward acceleration of 1.8m/s² will be----------N. [g = 10 m/s²]

As shown in the figure, a block of mass $\sqrt[]{3}kg$ is kept on a horizontal rough surface of coefficient of friction $\frac{1}{3\sqrt[]{3}}.$ The critical force to be applied on the vertical surface as shown at an angle 60° with horizontal such that it does not move, will be 3x. The value of x will be-------------.

[g = 10m/s² ; sin 60° = $\frac{\sqrt[]{3}}{2};$ cos60° = $\frac{1}{2}]$

A boy pushes a box of mass 2kg with a force $\overrightarrow{F}=\left(20\widehat{i}+10\widehat{j}\right)N$ on a frictionless surface. If the box was initially at rest, then-------------m is displacement along the x – axis after 10s.

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : Body 'P' having mass M moving with speed 'u' has head – on collision elastically with another body 'Q' having mass  'm' initially at rest. If m << M, Body 'Q' will have a maximum speed equal to '2u' after collision.

Reason R : During elastic collision, the momentum and kinetic energy are both conserved. In the light of the above statements, choose the most appropriate answer from the options given below

Two particles having masses 4g and 16g respectively are moving with equal kinetic energies. The ratio of the magnitudes of their linear momentum is n : 2. The value of n will be……….