Question

A 20 g piece of clay moves with a constant speed of 15 m/s. The piece of clay collides and sticks to a massive ball of mass 900 g suspended at the end of a string. a.) Calculate the momentum of the piece of clay before the collision. b.) Calculate the kinetic energy of the piece of clay before the collision. c.) What is the momentum of two objects after the collision

Answer 1

Explanation:

Given that,

Mass of the piece of clay, $m_1=20\ g=0.02\ kg$

Speed of the piece of clay, $u_1=15\ m/s$

Mass of the ball, $m_2=900\ g=0.9\ kg$

(a) The momentum of the piece of clay before the collision is given by :

$p_i=m_1u_1$

$p_i=0.02\ kg\times 15\ m/s$

$p_i=0.3\ kg-m/s$

(b) Let K is the kinetic energy of the piece of clay before the collision. It is given by :

$K=\dfrac{1}{2}m_1u_1^2$

$K=\dfrac{1}{2}\times 0.02\times (15)^2$

K = 2.25 Joules

(c) The piece of clay collides and sticks to a massive ball, its final velocity will be 0 and hence the momentum is 0.

So, the momentum of two objects after the collision is equal to :

$p_i=m_1u_1$

$p_i=0.02\ kg\times 15\ m/s$

$p_i=0.3\ kg-m/s$

Hence, this is the required solution.