Work, Energy and PowerNEET Physics · Class 11 · NCERT Chapter 5

Two stones of masses ma and 2 m are whirled in horizontal circles, the heavier one in a radius r 2 and the lighter one in radius r. the tangential speed of lighter stone is n times that of the value of heavier stone when they experience same centripetal forces. The value of n is:

A ball is thrown vertically downwards from a height of 20 m with an initial velocity v₀. It collides with the ground, loses 50 percent of its energy in collision and rebounds to the same height. The initial velocity v₀ is: (Take g = 10 ms⁻²)

What is the minimum velocity with which a body of mass m must enter a vertical loop of radius R so that it can complete the loop? www.vedantu.com 19

Consider a drop of rain water having mass 1 g falling from a height of 1 km. It hits the ground with a speed of 50 m/s. Take g constant with a value 10 m/s2. The work done by the (i) gravitational force and the (ii) resistive force of air is

A body initially at rest and sliding along a frictionless track from a height h (as shown in the figure) just completes a vertical circle of diameter AB = D. The height h is equal to

Body A of mass 4 m moving with speed u collides with another body B of mass 2m, at rest. The collision is head on and elastic in nature. After the collision the fraction of energy lost by the colliding body A is:

The radius of the circle, the period of revolution, initial position, and sense of revolution are indicated in the figure. The y-projection of the radius vector of the rotating particle P is: | | | | --- | --- | | \( q_1 = \frac{3Q}{4} \) | \( q_2 = \frac{3Q}{4} \) | | 3 m | | | y | x | | T = 4 s | P(t = 0) | y-projection of the radius vector of rotating particle P is:

Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine. The losses due to frictional force are 10% of the input energy. How much power is generated by the turbine ? (g = 10 m/s 2 )

The potential energy of a long spring when stretched by 2 cm is U. If the spring is stretched by 8 cm, potential energy stored in it will be :

At any instant of time t, the displacement of any particle is given by 2t – 1 (SI unit) under the influence of force of 5 N. The value of instantaneous power is (in SI unit):

Two bodies A and B of same mass undergo completely inelastic one dimensional collision. The body A moves with velocity v1 while body B is at rest before collision. The velocity of the system after collision is v2. The ratio v1 : v2 is

The kinetic energies of two similar cars A and B are 100 J and 225 J respectively. On applying brakes, car A stops after 1000 m and car B stops after 1500 m. If $F_A$ and $F_B$ are the forces applied by the brakes on cars A and B respectively, then the ratio of $\frac{F_A}{F_B}$ is

A bob of heavy mass $m$ is suspended by a light string of length $l$. The bob is given a horizontal velocity $v_0$ as shown in figure. If the string gets slack at some point $P$ making an angle $\theta$ from the horizontal, the ratio of the speed $v$ of the bob at point $P$ to its initial speed $v_0$ is:

A ball of mass 0.5 kg is dropped from a height of 40 m. The ball hits the ground and rises to a height of 10 m. The impulse imparted to the ball during its collision with the ground is (Take $g=9.8{\text{ m/s}}^2$)