Question

1. Two blocks travel along a level frictionless surface. Block A is initially moving to the right at 5.0 m/s, while block B is initially at rest. After the collision, block A continues to the right at 1.0 m/s. The mass of block A is 2.0 kg and the mass of block B is 3.0 kg. The positive x-direction is to the right. a. Find the final velocity of block B. Show your work. b. Is the sign of the change in momentum of block A as a result of the collision positive, negative, or is it zero

Answer 1

Answer: 2.67 m/s

Explanation:

Given

Mass of block A  is $m_a=2\ kg$

mass of block B is $m_b=3\ kg$

The initial velocity of block A $u_a=5\ m/s$

the initial velocity of block B is $u_b=0$

After collision velocity of block A is $v_a=1\ m/s$

Conserving momentum

$m_au_a+m_bu_b=m_av_a+m_bv_b\\\\2\times 5+3\times0=2\times 1+3\times v_b\\\\v_b=\dfrac{8}{3}=2.67\ m/s$

The momentum of block A after the collision is $P_a=2\times 1=2\ kg.m/s$

Therefore, there is no change in sign.