What did scientists predict the big bang should have left ? ?

Cosmic Microwave Background Radiations (CMBR)

Explanation:

The big bang was that point from which the universe started to exist, releasing a huge amount of Cosmic Microwave Background Radiations (CMBR) into the space.

CMBR is an electromagnetic radiation that are the the oldest remains of the big bang explosion. With the continuous expansion of the universe after the explosion, this radiations ere constantly spreading in all the direction for the last 13.5 billion years approximately.

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.