Question

A car of mass 1000km travelling at 32m/s dashes into a truck of mass 8000km moving in the same direction. with a velocity of 4m/s What is Velocity of that after the collision.​

Answer 1

Correct question :-

A car of mass 1000kg travelling at 32 m/s dashes into a truck of mass 8000 kg moving in the same direction with a velocity of 4 m/s after the collision the car bounces back with velocity 8 m /s what is the Velocity of the truck after collision?

➠ Given :-

☆ Before collision :-

➝ mass of car, $\sf m_1$ = 1000kg

➝ velocity of the car, $\sf u_1$ = 32 m/s

➝mass of the truck, $\sf m_2$ = 8000 kg

➝ velocity of the truck, $\sf u_2$ = 4 m /s

☆ After collision :-

➝ mass of car, $\sf m_1$ = 1000kg

➝ velocity of the car, $\sf v_1$ = -8 m/s (velocity of the car is negative as it is moving in the opposite direction )

➝ mass of the truck, $\sf m_2$ = 8000 kg

➠ To Find :-

Velocity of truck after the collision

➠ Solution :-

As no external force is acting on the system we can say that the momentum of the whole system is conserved

By applying law of conservation of momentum ,

Initial momentum = final momentum

$\longrightarrow \sf m_{1}u_{1} + m_{2}u_{1}= m_{2}v_{1} + m_{2}v_{2}$

$\longrightarrow \sf (1000)(32) + (8000)(4) = (1000)( - 8) + (8000) v_{2}$

$\longrightarrow \sf 32000 + 32000 = - 8000 + 8000 v_{2}$

$\longrightarrow \sf 64000 + 8000 = 8000 v_{2}$

$\longrightarrow \sf v_{2} = \cancel \frac{72000}{800}$

$\longrightarrow \boxed{ \bf v_{2} = {9ms}^{ - 1} }$

The velocity of the truck after collisions is 9m/s².