Question

the car of mass 1000 kg travelling at 20 metre per second collides with another car Bof mass 1000 kg travelling at 50% in the same direction after collision the velocity of a become 50 metre per second calculate the velocity of car Bafter collision ​

Answer 1

Answer: -20 m/s

The minus sign indicates that the car moves in the opposite direction.

Explanation:

Given,

Mass of Car A, $m_{A}$ = 1000kg

Mass of Car B, $m_{B}$ = 1000kg

Initial velocity of Car A, $u_{A}$ = 20 m/s

Initial velocity of Car B, $u_{B}$ = 50% of 20 m/s

                                                                = 10 m/s

Final velocity of Car B, $v_{A}$ = 50 m/s

According to law of conservation of momentum,

Velocity of system before collision = Velocity of system after collision

⇒ ($m_{A}$× $u_{A}$) + ($m_{B}$× $u_{B}$) = ($m_{A}$× $v_{A}$) + ($m_{B}$× $v_{B}$)

⇒ (1000 × 20) + (1000 × 10) = (1000 × 50) + (1000 × $v_{B}$)

⇒ 20000 + 10000 = 50000 + (1000 $v_{B}$)

⇒ 30000 =  50000 + (1000 $v_{B}$)

⇒ 30000 - 50000 = 1000 $v_{B}$

⇒ (-20000) = 1000 $v_{B}$

⇒ $v_{B}$ = (-20000) ÷ 1000

⇒ $v_{B}$ = -20 m/s