Question

James Bond is trying to escape his enemy on a speedboat but

his boat won't start and remains stationary in the water. His
enemy's boat is twice the mass of Bond's and collides with his
boat at 50 m/s. After the collision, the enemy boat is
completely stationary. How fast is Bond's boat moving?

Answer 1

100 m/s

Step-by-step explanation:

Mass the mass of Bond's boat is m₁. His enemy's boat is twice the mass of Bond's i.e. m₂ = 2 m₁

Initial speed of Bond's boat is 0 as it won't start and remains stationary in the water. The initial speed of enemy's boat is 50 m/s. After the collision, enemy boat is completely stationary. Let v₁ is speed of bond's boat.

It is the concept of the conservation of momentum. It remains conserved. So,

`m_1u_1+m_2u_2=m_1v_1+m_2v_2`

Putting all the values, we get :

`0+(2m_1)50=m_1v_1+(2m_2)(0)\\\\100m_1=m_1v_1\\\\v_1=100\ m/s`

So, Bond's boat is moving with a speed of 100 m/s after the collision.