Question

Which best summarizes a concept related to the work-energy theorem?

When work is positive, the environment does work on an object.
When work is negative, the environment does work on an object.
When work is positive, the kinetic energy in a system remains constant.
When work is negative, the kinetic energy in a system remains constant.

Answer 1

"When work is positive, the environment does work on an object."

Reason: the work–energy theorem states W_net = ΔK. Positive net work means energy is transferred into the object (environment does net positive work) and the object's kinetic energy increases; negative net work means energy is taken from the object (the object does net work on the environment) and its kinetic energy decreases.