Question

A ball moving with velocity of $9m/s$ collides with another similar stationary ball. After the collision both the balls move in directions making an angle of $30^{o}$ with the initial direction. After the collision their speed will be

• A. $2.6m/s$
• B. $5.2m/s$
• C. $0.52m/s$
• D. $52m/s$

Answer 1

Answer: (B)

$5.2m/s$

Answer 2

Initial horizontal momentum of the system = m × 9

Final horizontal momentum of the system = 2mv cos 30⁰

According to law of conservation of momentum, m × 9 = 2mv cos 30⁰

⇒ v = 5.2 m/s