Question

An unstable 3.0 kg object is flying through the air. It breaks up into to pieces. One of the pieces, which is 1.0 kg, completely stops and falls straight down to the ground. The other piece has now obtained a velocity of 8.1 m/s.

(a) What kind of collision is this?

(b) Draw a before and after picture (before = pre-collision and after = post- collision)

(c) Solve for the initial velocity of the “super-object.”

Answer 1

Let M = 3 kg

m1 = 1 kg, v1 = 0

m2 = 2 kg, v2 = 8.1 m/s

a) it is an inelastic collision.

beacsue, here momentum is only conserved but not kinetic energy.

b)

c) Let V is the speed of super-Objet

Apply conservation of momentum

initial momentum final momentum

M*V = m1*v1 + m2*v2

3*V = 1*0 + 2*8.1

==> V = 2*8.1/3

= 5.4 m/s