Question

A billiard ball moving at 5.00 m/s strikes a stationary ball of the same mass. After the collision, the first ball moves at 4.33 m/s at an angle of 30 degrees with respect to the original line of motion. a. Find the velocity (magnitude and direction) of the second ball after the collision. b. Was the collision inelastic or elastic? (make a claim and support with evidence.)

Answer 1

Answer

given,

initial speed of the billiard ball,u = 5 m/s

initial speed of second ball, u' = 0 m/s

after collision

final speed of first billiard, v = 4.33

at 30° from the original line

second velocity of the second billiard = ?

b)Collision between the two block is elastic.

mass of both the balls are not same

so,

θ₁ + θ₂ = 90°

 θ₁ = 30°

θ₂ = 90° - 30°

θ₂ = 60°

a) using conservation of momentum

  m u + m u' = m v cos θ₁ + m v' cos θ₂

  m x 5  + 0 = m x 4.33 x cos 30° + m x v' x cos 60°

  0.5 v' = 1.25

    v' = 2.5 m/s