A7.0−kg object is at rest on a perfectly frictionless surface when it is struck head-on by a 3.5−kg object moving at 13 m/s. if the collision is perfectly elastic, what is the speed of the 7.0−kg object after the collision? [hint: you will need two equations.]

4.72 m/s

Explanation:

Since the collision is perfectly elastic, both momentum and energy is conserved

Momenum:

Kinetic energy:

where m = 3.5 kg is the mass of the small moving object at speed v1 = 13 m/s. M = 7 kg is the mass of the big collided object with speed V post-collision. v2 is the speed of the small object post-collision.

Momentum:

Energy:

We can substitute

gravity

explanation:

305.7

explanation:

density =m/v

density =917/3.00

density = 305.

approximately = 305.7

in four significant figures