List of top Physics Questions on Work and Energy

A force $ \mathbf{F} = 2\hat{i} + b\hat{j} + \hat{k} $ is applied on a particle and it undergoes a displacement $ \mathbf{r} = \hat{i} - 2\hat{j} - \hat{k} $. What will be the value of $ b $, if the work done on the particle is zero?

An object of mass 1000 g experiences a time-dependent force $ \vec{F} = (2t \hat{i} + 3t^2 \hat{j}) \, \text{N} $. The power generated by the force at time $ t $ is:

A force $ \vec{f} = x^2 \hat{i} + y \hat{j} + y^2 \hat{k} $ acts on a particle in a plane $ x + y = 10 $. The work done by this force during a displacement from $ (0,0) $ to $ (4m, 2m) $ is Joules (round off to the nearest integer).

A force $ F = \alpha + \beta x^2 $ acts on an object in the x-direction. The work done by the force is 5 J when the object is displaced by 1 m. If the constant $ \alpha = 1 \, {N} $, then $ \beta $ will be:

A force $ \mathbf{F} = 2\hat{i} + b\hat{j} + \hat{k} $ is applied on a particle and it undergoes a displacement $ \mathbf{r} = \hat{i} - 2\hat{j} - \hat{k} $. What will be the value of $ b $, if the work done on the particle is zero?

A body of mass $2 \, \text{kg}$ begins to move under the action of a time-dependent force given by $\vec{F} = (6t \, \hat{i} + 6t^2 \, \hat{j}) \, \text{N}$. The power developed by the force at the time $t$ is given by:

A heavy iron bar of weight 12 kg is having its one end on the ground and the other on the shoulder of a man. The rod makes an angle $60^\circ$ with the horizontal, the weight experienced by the man is :

A car of mass 2000 kg is moving with a velocity of 18 km/h. Work done to stop this car is:

A bullet of mass 50 g is fired with a speed 100 m/s on a plywood and emerges with 40 m/s. The percentage loss of kinetic energy is :

A body is moving unidirectionally under the influence of a constant power source. Its displacement in time t is proportional to :

If a rubber ball falls from a height h and rebounds upto the height of h/2. The percentage loss of total energy of the initial system as well as velocity ball before it strikes the ground, respectively, are :

A force $ (3x^2 + 2x - 5) \, \text{N} $ displaces a body from $ x = 2 \, \text{m} $ to $ x = 4 \, \text{m} $. The work done by this force is _________ J.

A solid circular disc of mass 50 kg rolls along a horizontal floor so that its center of mass has a speed of 0.4 m/s. The absolute value of work done on the disc to stop it is ______ J.

An artillery piece of mass $ M_1 $ fires a shell of mass $ M_2 $ horizontally. Instantaneously after the firing, the ratio of kinetic energy of the artillery and that of the shell is:

The potential energy function (in joules) of a particle in a region of space is given as\[U = (2x^2 + 3y^3 + 2z).\]Here $ x $, $ y $, and $ z $ are in meters. The magnitude of the $ x $-component of force (in newtons) acting on the particle at point $ P (1, 2, 3) $ m is:

A particle is placed at the point $ A $ of a frictionless track $ ABC $ as shown in the figure. It is gently pushed toward the right. The speed of the particle when it reaches the point $ B $ is: (Take $ g = 10 \, \text{m/s}^2 $).