After a completely inelastic collision, two objects of the same mass and same initial speed are found to move away together at 1/3 their initial speed. find the angle between the initial velocities of the objects.

The angle is

Solution:

As per the question:

Mass of the objects are same, say m Kg each

Let their initial speed be 'u'

Both the objects move apart from each other at m/s

Now, the angle between the objects' initial velocities is given by using the law of conservation of momentum:

Now, applying the principle of momentum conservation along the horizontal axis:

Now, momentum conservation along vertical axis:

Now, angle between the initial velocities of the objects:

answer would be letter choice (a),   a ball resting on a shelf. would be another example of potential energy   >   stored energy > not moving.

a ball spinning on a finger   >   kinetic energy > moving energy

a ball rolling on the ground   >   kinetic energy   > moving energy

a   ball flying through the air   > kinetic energy   >   moving energy

hope that                                         : )

there are no contact forces mentioned on the list of choices that you've provided.