Work Power Energy

Assertion : The centre of mass of an electron and proton, when released moves faster towards proton. Reason : This is because proton is heavier.

A block of mass $2 \mathrm{~kg} F(t) \uparrow$ is free to move along the $x$-axis. It is at rest and from $t=0$ onwards it is subjected to a timedependent force $F(t)$ in the $x$ direction. The force $F(t)$ varies with…

A body of mass $10^3 \mathrm{~kg}$ moving with speed $2 \mathrm{~m} \mathrm{~s}^{-1}$ collides with a body of mass $15 \times 10^3 \mathrm{~kg}$ inelastically and sticks to it. Then loss in KE of the system will be

Initially spring is in its natural length. Now block of mass $0.25 \mathrm{~kg}$ is released, then find out maximum force by system on the floor.

Assertion: The kinetic energy does not change when a particle is moving in a uniform magnetic field. Reason : The velocity of the particle is not affected by magnetic field.

If potential energy is given by $U=\frac{a}{r^2}-\frac{b}{r}$. Then find out maximum force. (Given $a=2$, $b=4)$

Initially spring is in natural length and both the blocks are in rest condition. Then determine the maximum extension in the spring. $K=20 \mathrm{~N} \mathrm{~m}^{-1}$

With what minimum speed $v$ must a small ball should be pushed inside a smooth vertical tube from a height $h$, so that it may reach the top of the tube? Radius of the tube is $R$. (Assume radius of cross-section of…

Assertion : Work done in moving a body over a closed loop is zero for every force in nature. Reason : Work done does not depend on nature of force.

Three bodies, a ring, a solid cylinder and a solid sphere roll down the same inclined plane without slipping. They start from rest. The radii of the bodies are identical. Which of the bodies reaches the ground with…

A body is moved in straight line by machine with constant power. The distance travelled by it in time duration $t$ is proportional to

A spring of spring constant $5 \times 10^3 \mathrm{~N} \mathrm{~m}^{-1}$ is stretched initially by $5 \mathrm{~cm}$ from the unstretched position. The work required to stretch it further by another $5 \mathrm{~cm}$ is