A man of mass 70 kg jumps to a height of 0.8 m from the ground, then the momentum transferred by the ground to the man is
(g = 10 m/s\(^{-2}\)):
Step 1: Calculate the initial velocity required to reach 0.8 m.
Using the formula \( v^2 = u^2 + 2as \) and rearranging for \( u \) when \( v = 0 \), \( a = -g \), and \( s = 0.8 { m} \):
\[ 0 = u^2 - 2 \times 10 \times 0.8 \Rightarrow u^2 = 16 \Rightarrow u = 4 { m/s}. \] Step 2: Calculate the momentum transferred.
\[ p = m \times u = 70 \times 4 = 280 { kg ms}^{-1}. \] The momentum calculation involves the mass and initial velocity, assuming no air resistance and perfect energy conversion.
In the given circuit, the electric currents through $15\, \Omega$ and $6 \, \Omega$ respectively are

Find the least horizontal force \( P \) to start motion of any part of the system of three blocks resting upon one another as shown in the figure. The weights of blocks are \( A = 300 \, {N}, B = 100 \, {N}, C = 200 \, {N} \). The coefficient of friction between \( A \) and \( C \) is 0.3, between \( B \) and \( C \) is 0.2 and between \( C \) and the ground is 0.1.

A truck of mass 1200 kg moves over an inclined plane raising 1 in 20, with a speed of 18 kmph. The power of the engine is
(g = 10 m/s\(^{-2}\)):
A thin circular ring and a circular disc have the same mass and moment of inertia about their centers perpendicular to the plane.
Then the ratio of their radii is: