Can someone plz explain :
Two cars have the same mass, the first car is moving towards the east and the second is
stationary. If the two cars merge together after a collision and head towards the east their speed
after the collision is equal to.......
A)1/4vi b)1/2vi c)vi d) 2vi

Question

Answered

Sagot :

Facundo3141592id Facundo3141592id · Answer 1

Answer: Option b, the final velocity is half of the initial velocity.

Explanation:

Here we will use the conservation of the total momentum of a system.

This means that the total momentum at the beginning must be the same as the final momentum.

Where momentum is:

P = M*v

Initially, we have two cars, both with the same mass M, and only one of them has a velocity v.

Then the initial momentum is:

P = M*v + M*0 = M*v

After the collision, the two cars move together. Then the total mass that is moving is equal to the sum of the masses of the cars, this is 2*M

and we can suppose that the two cars move at a final velocity v'

Then the final momentum is:

P' = (2*M)*v'

Now we use the conservation of momentum, then:

P = P'

M*v = (2*M)*v'

Now we need to solve this for v'

(M*v)/(2*M) = v'

v/2 = v'

This means that the final velocity is half of the initial velocity.

Then the correct option is option b.