Question

A body of mass 5 kg moving with a speed of 3 ms. collides head on with a body of mass 3 kg moving in the opposite direction at a speed of 2 ms. The first body stops after the collision. The final velocity of the second body is​

Answer 1

Answer:

1ms per sec because the speed decrease

Answer 2

Answer:

The final velocity of second body is 3 m/s.

Explanation:

Body moving in same direction (First body):

Mass of body, $m_1=5$ kg

Speed of body, $u_1=3$ m/s

Body moving in opposite direction (Second body):

Mass of body, $m_2=3$ kg

Speed of body, $u_2=-2$ m/s (moving in opposite direction)

After collision, the first body stops, i.e.,

$v_1=0$ m/s

Using law of conservation of momentum,

$m_1u_1+m_2u_2=m_1v_1+m_2v_2$

Substituting the values, we get

($5$ × $3$) + ($3$ × ($-2$)) = ($5$ × $0$) + 3$v_2$

⇒ 15 - 6 = 0 + 3$v_2$

⇒ 9 = 3$v_2$

⇒ $v_2$ = 3 m/s

Observe that the value of final velocity is positive.

Thus, the second body moves in the forward direction after collision with  the velocity 3 m/s.

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