Question

Ball B, moving in the positive direction of an x axis at speed v, collides with stationary ball A at the origin. A and B have different masses. After the collision, B moves in the negative direction of the y axis at speed v/3. In what direction does A move, as an angle with respect to the x axis?

Answer 1

Answer:

$\theta = -18.43 degree$

Explanation:

As we know that there is no external force on two balls during the collision

So we can say that the momentum of two balls will remains conserved

So here we will have

$P_i = m_b v \hat i$

now final momentum will be same as that of initial momentum so we can say

$P_f = P_a + m_b\frac{v}{3}\hat j$

now we have

$m_b v \hat i= P_a + m_b\frac{v}{3} \hat j$

now we have

$P_a = m_b v\hat i - \frac{m_b v}{3} \hat j$

now the direction of motion of ball A is given as

$tan\theta = \frac{-(m_b v/3)}{m_b v}$

$tan\theta = -\frac{1}{3}$

$\theta = -18.43 degree$