# Two cars are moving along a straight highway in the same direction: the first at a speed v

Two cars are moving along a straight highway in the same direction: the first at a speed v, and the second at a speed of 3 v. What is the speed of the second car relative to the first?

V1 = v.

V2 = 3 * v.

V21 -?

Since the cars are moving in one direction, according to the law of relativity, the speed of the second car relative to the first V21 will be the difference: the speed of the second car relative to the ground V2 and the speed of the first car V1 relative to the ground: V21 = V2 – V1.

V21 = 3 * v – v = 2 * v.

Answer: the speed of the second car relative to the first is V21 = 2 * v.

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.