Question

A trolley of mass 2.0 kg moving to the right at 0.3 ms-1 collides with a trolley of mass 4.0 kg which is at rest. The 4.0 kg trolley moves off to the right at 0.7 ms-1 . Show that the 2.0 kg trolley rebounds and moves off to the left at 1.1ms-1

Answer 1

Answer :

Mass of trolley 1 = 2kg

Mass of trolley 2 = 4kg

★ Before collision :

• Initial velocity of 1 = 0.3 m/s
• Initial velocity of 2 = zero

Net initial momentum of the system will be ;

➠ m₁u₁ + m₂u₂

➠ 2(0.3) + 4(0)

➠ 0.6

★ After collision :

• Final velocity of 2 = 0.7 m/s

We have to prove that, final velocity of trolley 1 after collision will be -1.1 m/s$.$

Here negative sign shows opposite direction.

Net final momentum of the system will be :

➠ m₁v₁ + m₂v₂

➠ 2v₁ + 4(0.7)

➠ 2v₁ + 2.8

Initial momentum of the system will be equal to the final momentum of the system.

➝ 0.6 = 2v₁ + 2.8

➝ 0.6 - 2.8 = 2v₁

➝ v₁ = -2.2/2

➝ v₁ = -1.1 m/s

Hence proved!!