Question

A 10 kg box slides on a horizontal frictionless surface at 8m/s. It strikes another 7kg box at rest. What is the final speed of two boxes slide together after the collision?

Answer 1

$\textbf{ Hello Mate! }$

Case 1 ( Before collision )

Mass of 1st box is 10 kg moving witg 8 m/s speed. Where as other box was at rest ( u = 0 ) ofass 7 kg.

Total Initial Momentum = m1u1 + m2u2

= (10)(8) + (7)(0)

= 80 kg m/s

Case 2 ( After collision )

1st box and second box moves together with same velocity.

Total final mentum = m1v1 + m2v2

But as velocity will be now equal.

= v ( m1 + m2 )

= v ( 10 kg + 7 kg )

= 17 v

T Initial Momentum = T Final Momentum

80 = 17 v

80 = 17 v

4.71 m/s = v

$\textbf{ F velocity of 2 boxes is 4.71 m/s }$

Have great future ahead!