Question

An object of mass m moves to the right with a speed v. It collides head-on with an object of mass 3m moving with speed v/3 in the opposite direction. If the two objects stick together, what is the speed of the combined object, of mass 4m, after the collision?

a. 2v
b. v/2
c. 0

Answer 1

Therefore, the correct option is c: 0.

Step-by-step explanation:

We can find the speed of the combined object by conservation of linear momentum:

`p_(i) = p_(f)`

`m_(1)v_{1_(i)} + m_(2)v_{2_(i)} = m_(1)v_{1_(f)} + m_(2)v_{2_(f)}`

Where:

"i" is for initial and "f" is for final

m₁: is the mass of the first object = m

m₂: is the mass of the second object = 3m

v₁: is the velocity of the first object

v₂: is the velocity of the second object

`mv - 3m(v)/(3) = (m + 3m)v_(f)`

`mv - mv = 4mv_(f)`

`v_(f) = 0`

Therefore, the correct option is c: 0.

I hope it helps you!