What force is necessary to accelerate a 70- kg object at a rate of 4.2 m/ s

Describe the path of a ray that approaches a mirror parallel to the principal axis.

30 points - when can a theory be modified if a new type of technology allows for new observations that raise new questions? a. immediately, while the questions about the theory are being asked b. after new hypotheses related to the theory are tested in experiments c. only after the new observations disprove all parts of the theory d. while scientists begin to think about how the theory could improve

What object a collides with object b and bounces back its final momentum is?