A person whose mass is 90kg is standing on a smooth horizontal platform. He throws a rock of mass 10kg horizontally on the same surface. If the distance between the person and the rock after 10 seconds is 10 m, what is the kinetic energy of the person?
A. 0.45 J
B. 4.5 J
C. 0.9 J
D. 0 J
Answer:B
A person whose mass is 90kg is standing on a smooth horizontal platform. He throws a rock of mass 10kg horizontally on the same surface. If the distance between the person and the rock after 10 seconds is 10 m, what is the kinetic energy of the person?
A. 0.45 J B. 4.5 J C. 0.9 J D. 0 J