Newton's Laws of Motion

The concept of pseudo-force is necessary to explain observations made by an observer who is:

If the acceleration of a lift is equal to the acceleration due to gravity ($g$) downwards, the person inside feels:

Which of these forces does NOT exist in reality and is only used to simplify calculations in certain frames?

A rotating platform is a:

Newton's Laws of Motion are strictly valid only in inertial frames. If an observer is in a non-inertial (accelerating) frame, pseudo forces must be introduced to apply Newton's Second Law ($F = ma$). Consider the sequence of frames shown in the diagram. Frame $S$ is known to be inertial. If Frame $A$ moves at a constant velocity relative to $S$, Frame $B$ moves with a constant acceleration relative to $A$, and Frame $C$ moves at a constant velocity relative to $B$, in which of these frames will an observer perceive pseudo forces acting on a stationary object?

When a car suddenly turns left, a bag on the seat slides to the right. The real force responsible for this motion relative to the ground is:

An object is at rest in an inertial frame. An observer in a non-inertial frame accelerating at $\vec{a}$ will see the object have an acceleration of:

A cabin is sliding down a frictionless inclined plane that makes an angle $\theta$ with the horizontal. An observer inside the cabin hangs a small pendulum from the ceiling. To correctly describe the pendulum's equilibrium position relative to the cabin using Newton's second law, the observer must account for the cabin's non-inertial nature by introducing a pseudo-force. In which direction will the pendulum string point when it is at rest relative to the cabin?

In a free-falling lift, what happens to the buoyant force acting on an object submerged in a liquid?

A body of mass $m$ is at rest on a smooth surface in a frame which is rotating with angular velocity $\omega$. The pseudo-force on the body at a distance $r$ from the axis is:

Newton's second law is also known as the law of:

An object of mass $5 \text{ kg}$ is accelerated from $2 \text{ m/s}$ to $10 \text{ m/s}$ in $2 \text{ s}$. The force acting on it is:

Why is the weight of an object different at different places on Earth?

The relation between $g$ and $G$ is given by (where $M$ is mass of Earth and $R$ is radius):

Two stationary point masses, $M$ and $9M$, are separated by a distance $L$ in space. A third small point mass $m$ is placed at a point $P$ on the line segment joining the two masses. If the net gravitational force acting on $m$ is zero, what is the distance $x$ of point $P$ from the smaller mass $M$?

A body of mass $10 \text{ kg}$ is moving with a velocity of $5 \text{ m/s}$. A force of $20 \text{ N}$ is applied in the direction of motion for $2 \text{ s}$. The final momentum is:

A truck and a car are moving with the same kinetic energy. If equal retarding forces are applied to both, which will come to rest in a shorter distance?

At what height $h$ above the Earth's surface is the acceleration due to gravity $g/n$ (where $g$ is surface gravity)?

A shell of mass $200 \text{ g}$ is fired by a gun of mass $100 \text{ kg}$. If the muzzle speed of the shell is $80 \text{ m/s}$, then the recoil speed of the gun is:

If the distance between the Earth and the Sun were halved, the duration of the year would be:

A body is free to rotate about a pivot. If a force is applied, it will undergo:

If the moment of a force is $50 N m$ and the force is $10 N$, the distance is:

The moment of a force is also called the ________ effect of force.

To rotate an object, the line of action of the force must not pass through the:

For a given force, the turning effect is least when the force is applied:

A force $F$ acts on a rod at a distance $x$ from the pivot. If another force $2F$ acts at a distance $x/2$ in the same direction on the same side of the pivot, the total moment is:

The 'arm of force' in the calculation of torque refers to the:

A $60\,kg$ man stands on a uniform $20\,kg$ plank of length $4\,m$. The plank is supported at its ends. If the man stands $1\,m$ from the left end, the reaction at the right support is $(g=10\,m/s^2)$:

Two parallel and opposite forces of $20\,N$ each act on a body at a separation of $50\,cm$. The net force and net torque are:

A uniform beam of mass $10\,kg$ and length $4\,m$ is supported at one end and at a point $1\,m$ from the other end. Find the reaction at the end support.