Question

A boy of 70kg mass is running with a velocity of 10m/s. He jumps over a stationary cart of 20kg while running. Find the velocity of cart after jumping of boy.

Answer 1

Answer:

$\boxed{\mathfrak{Velocity \ of \ cart \ after \ jumping \ of \ boy = 7.78 \ m/s}}$

Explanation:

Mass of boy ($\rm m_b$) = 70 kg

Initial velocity of boy ($\rm v_b$) = 10 m/s

Mass of cart ($\rm m_c$) = 20 kg

Initial velocity of cart ($\rm v_c$) = 0 m/s (Stationary)

Let 'v' be the velocity of cart after jumping of boy.

By using conservation of linear momentum we get:

$\rm \implies m_b v_b + m_c v_c = (m_b + m_c)v$

By substituting value we get:

$\rm \implies 70 \times 10 + 20 \times 0 = (70 + 20)v \\ \\ \rm \implies 700 + 0 = 90v \\ \\ \rm \implies v = \frac{700}{90} \\ \\ \rm \implies v = \frac{70}{9} \\ \\ \rm \implies v = 7.78 \: m {s}^{ - 1}$