Chapter 6, Problem 61EAP

Astronauts in space "weigh" themselves by oscillating on a spring. Suppose the position of an oscillating 75 kg astronaut is given by $x=(0.30\text{m)sin((}\pi \text{rad/s)×}t\text{)}$ , where t is in s. What force does the spring exert on the astronaut at (a) t = 1.0 s and (b) s? Note that the angle of the sine function is in radians.