Question

A truck weighing 2500kg and moving with a velocity
10ms-1 collides with car weighing 500kg moving
with 5ms-1. After collision, the car is moving with a
velocity of Sms-1 then with what velocity the truck is
moving?
A 7.4ms-1
B. 8.4ms-1
C. 6.4ms-1
D. 9.4ms-1​

Answer 1

Correct question :-

A truck weighing 2500kg and moving with a velocity 10m/s collides with car weighing 500kg moving with 5m/s After collision, the car is moving with a

velocity of 8m/s then with what velocity the truck is moving?

Answer :-

9.4m/s

Explanation :-

Given :

Mass of the truck,m_1 = 2500kg

Initial velocity of the truck,u_1 = 10m/s

Mass of the car,m_2 = 500kg

Initial velocity of the car,u_2 = 5m/s

Final velocity of the car,v_2 = 8m/s

To Find :

Velocity of the truck after collision,v_1 = ?

Solution :

According the conversation law of momentum,

$\sf{}m_1u_1+m_2u_2=m_1v_1+m_2v_2$

Put their values and find “v_1”

$\sf{}\implies 2500kg\times 10m/s+500kg\times 5m/s=2500\times v_1+500\times 8$

$\sf{}\implies 25000kg\ m/s+2500kg\ m/s=2500\times v_1+4000kg\ m/s$

$\sf{}\implies 27500kg\ m/s=2500\times v_1$

$\sf{}\implies 27500kg\ m/s-4000kg\ m/s=2500\times v_1$

$\sf{}\implies 23500kg\ m/s=2500kg \times v_1$

$\sf{}\implies \dfrac{23500kg\ m/s}{2500kg}=v_1$

$\sf{}\implies v_1=\dfrac{47m/s}{5}$

$\sf{}\implies v_1=\dfrac{47m/s}{5}$

$\sf{}\implies v_1=9.4m/s$

Therefore,after the collision truck is moving with a velocity 9.4m/s

Hence, option D is correct.