Question

Two identical round blue balls are moving directly toward one another at the same speed v. What is the total kinetic energy of the system of the two objects?

1) 4mv² since (2v)² = 4v²
2) none of these
3) mv² since energy is a scalar
4) 1/2mv² from the definition of kinetic energy
5) zero since (v - v)² = 0

Answer 1

The total kinetic energy of two identical balls moving toward each other at speed v is KE(total) = mv², as kinetic energy is a scalar and is calculated for each ball separately before being summed.

Step-by-step explanation:

The total kinetic energy of a system consisting of two identical round blue balls moving directly toward one another at the same speed v is obtained by summing the kinetic energy of each ball. The kinetic energy of one ball is given by the formula KE = 1/2mv², where m is the mass and v is the velocity. Thus, since there are two balls, the total kinetic energy of the system would be KE(total) = 1/2mv² + 1/2mv² = mv².