Question

A 2 kg object traveling at 5 m/s on a frictionless horizontal surface collides head-on with and sticks to a 3 kg object initially at rest. Which of the following correctly identifies the change in total kinetic energy and the resulting speed of the objects after the collision?

Kinetic Energy Speed
(A) Increases 2 m/s
(B) Increases Soold 3.2 m/s
(C) Decreases 2 m/s
(D) Decreases 3.2 m/s

Answer 1

Decreases 2 m/s

Step-by-step explanation:

This is an inelastic collision :

m1u1 + m2u2 = (m1 + m2)v

Where ;

m1 and u1 = mass and initial velocity of object 1

m2 and u2 = mass and initial velocity of object 2

v = final velocity of the objects

m1 = 2kg ; m2 = 3kg ; u1 = 5 m/s ; u2 = 0 ; v =?

m1u1 + m2u2 = (m1 + m2)v

(2*5) + (3*0) = (2 + 3)v

10 + 0 = 5v

10 = 5v

v = 10/5

v = 2m/s