Thermal expansion causes a change
in the
of a substance.

Thermal expansion changes the space between particles of a substance

the diagram which shows forces as either balanced = same speed or unbalanced = accelerarting

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.