Rocket engines lift a rocket from the earth surface because hot gas with high velocity
Push against the earth
Push against the air
React against the rocket and push it up
Heat up the air which lifts the rocket
A mass of $100\,g$ strikes the wall with speed $5\,m/s$ at an angle as shown in figure and it rebounds with the same speed. If the contact time is $2 \times {10^{ - 3}}\,\sec $, what is the force applied on the mass by the wall
A jet engine works on the principle of
A projectile is fired with velocity $u$ at an angle $\theta$ with horizontal. At the highest point of its trajectory it splits up into three segments of masses $m, m$ and $2 \,m$. First part falls vertically downward with zero initial velocity and second part returns via same path to the point of projection. The velocity of third part of mass $2 \,m$ just after explosion will be
A bullet of mass $50$ gram is fired from a $5 \,kg$ gun with a velocity of $1km/s$. the speed of recoil of the gun is .......... $m/s$
A simple pendulum of length $1 \mathrm{~m}$ has a wooden bob of mass $1 \mathrm{~kg}$. It is struck by a bullet of mass $10^{-2} \mathrm{~kg}$ moving with a speed of $2 \times 10^2 \mathrm{~ms}^{-1}$. The bullet gets embedded into the bob. The height to which the bob rises before swinging back is. (use $\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$ )