PLEASE HELP ASAP with the questions attached on special relativity for Physics 12. SHOW STEPS thanks!!! Will mark brainliest.

What are atoms of the same element with varying number of neutrons

Ais not a mixture. colloid compound suspension solution

The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.