Question

A truck weighing $5\times {10}^{3}kgf$ and a cart weighing $500kgf$ are moving with the same speed. So, kinetic energy of the truck is:

• A. same as that of the cart
• B. $10$ times the kinetic energy of the cart
• C. $0.1$ times the kinetic energy of the cart
• D. $100$ times the kinetic energy of the cart

Answer 1

Answer: (B)

$10$ times the kinetic energy of the cart

Mass of the truck, $m_1=5\times {10}^{3}kg$, mass of cart, $m_2=500kg$.

Since speeds are same, kinetic energy is directly proportional to the mass of the object.

$K\propto m$

$\therefore$ $\frac{K_1}{K_2}=\frac{m_1}{m_2}=\frac{5\times {10}^3}{500}=\frac{10}{1}$

or, $K_1=10K_2$