Laws of motion practice · Medium

Assertion(A): A glass ball is dropped on concrete floor can easily get broken compared, if it is dropped on wooden floor.

Reason(R): On concrete floor, glass ball will take less time to come to rest.

A lift is moving upwards with an acceleration $a$. The force exerted by a person of mass $M$ on the floor of the lift will be

Five persons $\mathrm{A}, \mathrm{B}, \mathrm{C}, \mathrm{D}$ and $\mathrm{E}$ are pulling a cart of mass $100 \mathrm{~kg}$ on a smooth surface and the cart is moving with an acceleration of $3 \mathrm{~m} \mathrm{~s}^{-2}$ in the east direction. If another person $\mathrm{F}$ comes and starts pulling the cart with a force of $100 \mathrm{~N}$ due west, then the acceleration of the cart will be

A light spring balance hangs from the hook of the other light spring balance and a block of mass M kg hangs from the former one. Then the true statement about the scale reading is

One end of a long string of linear mass density $8.0 \times 10^{-3} \mathrm{~kg} \mathrm{~m}^{-1}$ is connected to an electrically driven tuning fork of frequency $256 \mathrm{~Hz}$, such that the frequency of tuning fork is equal to that of the string. The other end passes over a pulley and is tied to a pan containing a mass of $90 \mathrm{~kg}$. The pulley end absorbs all the incoming energy so that reflected waves at this end have negligible amplitude. At $t=0$, the left end (fork end) of the string $x=0$ has zero transverse displacement $(y=0)$ and is moving along positive $y$ direction. The amplitude of the wave is $5.0 \mathrm{~cm}$. Then the transverse displacement $y$ (in m) as function of $x$ and $t$ that describes the wave on the string. (Take $g=9.8 \mathrm{~m} / \mathrm{s}^2$ )

A man of mass $60 {~kg}$ climbed down using an elevator. The elevator had an acceleration of $4 {~ms}^{-2}$. If the acceleration due to gravity is $10 {~ms}^{-2}$, the man's apparent weight on his way down is

Law that proves that different masses accelerate to the earth at the same rate, but with different forces is

Swimming is possible on account of

In an ideal string tension at all points of all string will be

Conservation of momentum in a collision between particles can be understood from

Which of the following sets of forces can not have resultant force equal to zero. (All forces are in newton).

The frictional force on a block of weight $10 \mathrm{~N}$ of area $0.1 \mathrm{~m}^2$ is $5 \mathrm{~N}$. If area of block is increased to $0.2 \mathrm{~m}^2$, keeping weight and material same; the frictional force on new block would be (assume all other conditions to be same)

A bullet of mass 28 grams is fired from a rifle of mass 11 kg with a velocity of 100 m/s. The recoil of the rifle is

The impulse on a particle due to a force acting on it during a given time interval is equal to the change in its

Statement-I: Angle of repose is equal to angle of limiting friction.
Statement-II: When the body is just at the point of motion, the force of friction in this stage is called as limiting friction.

A body of mass 60 kg is pushed with just enough force to start it moving on a rough surface with ${\mu _s} = 0.5$ and ${\mu _k} = 0.4$ and the force continues to act afterwards. The acceleration of the body is $\left( {\mathrm{in}\,m/{{\sec }^2}} \right)$

A body of mass 10 kg is moving on a horizontal surface by applying a force of 10 N in forward direction. If body moves with constant velocity, the work done by force of fiction for a displacement of 2m is

The laws of Newton's are applicable

Two skaters $A$ and $B$ of masses $50 \mathrm{~kg}$ and $70 \mathrm{~kg}$ respectively stand facing each other $6 \mathrm{~m}$ apart. Then they pull on a rope stretched between them. How far has each moved when they meet?

A person is measuring his weight by standing on a weighing machine inside a lift. When the lift is at rest, the machine shows his weight to be 55 kg. In between the floor when the lift is moving up with a constant speed of 10 km/hr, he again measures his weight, which is

A body of mass 0.05 kg is observed to fall with an acceleration of 9.5 $m{s^{ - 2}}$. The opposing force of
air on the body is $\left( {9.8\,\,m{s^{ - 2}}} \right)$

Statement I: Newton's second law is applicable on a body with respect to an inertial frame of reference.
Statement II: In order to apply Newton's second law on a body observed from a non-inertial frame of reference. We apply line pseudo force an imaginary force.

A force of $0.03 {~N}$ acts on a body of mass $0.5 {~kg}$. which is initially at rest for a duration of 10 seconds. Then find the momentum acquired by the body.

In the above Question, if the string C is stretched slowly, then