Question

A man weighing 60 kg runs along the rails with a velocity of 18 km/h and jumps into a car of mass 1 quintal (100 kg) standing on the rails. Calculate the velocity with which car will star traveling along the rails ​

Answer 1

Given:-

Before Collision

• Mass of the man (m¹)= 60kg

• Initial Velocity of the man (u¹) = 18km/h = 5m/s

• Mass of Car (m²) = 100kg

• Initial Velocity of the Car (u²) = 0m/s

After Collision

• Mass of the man (m²)= 60kg

• Mass of Car (m²) = 100kg

• Velocity = v¹ = v² = ?

To Find:-

• The Velocity with which car will start travelling.

Concept used:-

• Conservation of Momentum.

Now,

According to the Conservation of Momentum.

Total Momentum before Collision = Total Momenta After Collision

• As the man jump into the car so, The velocity will be same for both

m¹u¹ + m²u² = m¹v¹ + m²v²

(60)(5) + (100)(0) = (m¹ + m²)v

300 + 0 = (60 + 100)v

300 = 600v

v = 300/600

v = 0.5m/s.

Hence, The Car will start travelling along the rails with the Velocity of 0.5m/s.