Asample of a substance has a high density, yet a low particle motion. this sample must be a
a) gas.
b) liquid.
c) plasma.
d) solid.

The correct answer is option (D).

Explanation:

In solid state there is strong inter molecular forces of attraction between particles therefore the motion of particles are completely restricted where as in liquids and gases, the inter molecular forces are comparatively weak and thus the motion of particles are not restricted.

A sample of a substance has a high density which means that volume of occupied by the substance is less .This is because volume is inversely proportional to the density of a substance. High density means that large numbers of particles are present in a unit volume of that substance and that is state of substance is a solid state.

Hence, the correct answer is option (D).

probably not if net force is zero

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.