Laws Of Motion - Mechanics - Physics Previous Year Questions

An aircraft is moving with uniform velocity $150 \mathrm{~m} / \mathrm{s}$ in the space. If all the forces acting on it are balanced, then it will

A block of mass $M$ is pulled along a smooth horizontal surface with a rope of mass $m$ by force $F$. The acceleration of the block will be

A block of mass \(m\) is moving on rough horizontal surface with momentum \(p\). The coefficient of friction between the block and surface is \(\mu\). The distance covered by block before it stops is [\(g=\) acceleration due to gravity]

A body of mass \(2 \mathrm{~kg}\) is acted upon by two forces each of magnitude \(1 \mathrm{~N}\) and inclined at \(60^{\circ}\) with each other. The acceleration of the body in \(\mathrm{m} / \mathrm{s}\) is [\(\cos 60^{\circ}=0.5\)]

The weight of a man in a lift moving upwards with an acceleration 'a' is 620 N. When the lift moves downwards with the same acceleration, his weight is found to be 340 N. The real weight of the man is

A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring balance reads \(49 \mathrm{~N}\), when the lift is stationary. If the lift moves downward with an acceleration of \(5 \mathrm{~m} / \mathrm{s}^2\), the reading of the spring balance will be \((\mathrm{g}=9.8 \mathrm{~m} / \mathrm{s}^2)\)

A door \(1.2 \mathrm{~m}\) wide requires a force of \(1 \mathrm{~N}\) to be applied perpendicular at the free end to open or close it. The perpendicular force required at a point \(0.2 \mathrm{~m}\) distant from the hinges for opening or closing the door is

A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring balance reads \(49 \mathrm{~N}\), when the lift is stationary. If the lift moves downward with an acceleration of \(5 \mathrm{~m} / \mathrm{s}^2\), the reading of the spring balance will be \(\left(g=9.8 \mathrm{~m} / \mathrm{s}^2\right)\)

A machine gun fires bullets of mass \(30 \mathrm{~g}\) with velocity of \(1000 \mathrm{~m} / \mathrm{s}\). The man holding the gun can exert a maximum force of \(300 \mathrm{~N}\) on it. How many bullets can he fire per second at most?

Which one of the following is 'NOT' a contact force?

The pulleys and strings shown in figure are smooth and of negligible mass. For the system to remain in equilibrium, angle $\theta$ should be

The mass of the lift is 200 kg , when it ascends with an acceleration of $4 \mathrm{~m} / \mathrm{s}^2$ then the tension in the cable supporting the lift will be [Given: Acceleration due to gravity $g=10 \mathrm{~m} / \mathrm{s}^2$ ]

Two identical blocks each of mass ' M ' attached to the ends of a massless inextensible string which passes over a pulley with a fixed axis as shown below. A small mass ' $m$ ' is now placed on the block B. The acceleration with which the two blocks move together is [g = gravitational acceleration]

Two blocks of masses 6 kg and 4 kg are placed in contact with each other on a smooth surface as shown. If a force of 5 N is applied on a heavier block, the force on the lighter block is

Force is applied to a body of mass 3 kg at rest on a frictionless horizontal surface as shown in the force against time (F-t) graph. The speed of the body after 1 s is

Which one of the following person is in an inertial frame of reference?

A conveyor belt is moving with constant velocity (V). Sand is being dropped on the belt at the rate of $\mathrm{M} \mathrm{kg} / \mathrm{s}$. The force necessary to keep the belt moving with a constant velocity $\mathrm{V} \mathrm{m} / \mathrm{s}$ will be

A child stands on a weighing machine inside a lift. When the lift is going down with acceleration $\mathrm{g} / 3$, the machine shows a reading 20 N . When the lift goes upwards with acceleration $\mathrm{g} / 3$, the reading would be ( $\mathrm{g}=$ gravitational acceleration)

A constant force acts on two different masses independently and produces accelerations $\mathrm{A}_1$ and $A_2$. When the same force acts on their combined mass, the acceleration produced is

The weight of man in a stationary lift is $w_1$ and when it is moving downwards with uniform acceleration ' a ' is $\mathrm{w}_2$. If the ratio $\mathrm{w}_1: \mathrm{w}_2=4: 3$, then the value of ' a ' is ( $\mathrm{g}=$ acceleration due to gravity)