Question

Particle 1 has a velocity v1 = 2 m/s and a
mass m1 = 2 kg . This particle collides with
particle 2 of mass m2 = 6 kg , which is at rest,
and then the two particles stick together.
The speed of the conglomerate particle is

1. 2 m/s
2. 1 m/s
3. 0.5 m/s
4. 0.75 m/s
5. 1.5 m/s

Answer 1

The ratio of the final kinetic energy to the
initial kinetic energy is
1. 0.25
2. 0.1
3. 0.8
4. 1
5. 0.5

Answer 2

m1v1+m2v2 = (m1+m2)V
Find V.

Answer 3

reminds me of a weighted average .....

Answer 4

so it's (2*2)+(6*0)=(2+6)V

Answer 5

Yes.

Answer 6

@amistre64 It IS a weighted average. It's just a form of the expected velocity.
It's interesting how topics branch in and out.

Answer 7

agreed :)

Answer 8

So the answer would be .5m/s?

Answer 9

If you did it right, yes.
Remember to use the final mass for the KE.

Answer 10

And to find kinetic energy I use .5mv^2? But there are two masses

Answer 11

Find KE 1 and KE 2 and then KE final.

Answer 12

Oh ok but I add the first two?

Answer 13

Yes.

Answer 14

The second mass has 0 KE since it is at rest.

Answer 15

Thank you :)

Answer 16

You're welcome.