# Physics Concepts

1. Dec 19, 2003

### ScoutFCM

How am I supposed to figure out these concepts? No problems to do, but I'm just not understanding the material/concepts? anyone care to explain/teach me?

5.) Weight of a man who is throwing a bag of potatoes?

7/8) Net acceleration of a body on a curved path

10) Kinetic energy of a rocket after firing its engine

14) Acceleration of a point on a wheel

18) kinetic enregy expressed in terms of momentum

19) distance traveled & energy lost by skier

20) escape speed for spacecraft

21) tension and agular speed of a rock on a string

22) trajectories after a football tackle

23) power wasted by falling water

2. Dec 19, 2003

### Jupiter

The weight of the man does not increase. However, the normal force exerted by the ground on the man increases. This is because the man must exert a force F on the potatoes to throw it into the air. The potatoes exert the same force F on the man. So the net force acting on the man is his weight W plus F. Since the man does not accelerate, the normal force must be the same. So the man may feel heavier, but his weight is the same.

I need more information than this. ANY body can be said to be traveling on a curved path.

Again, I can't describe this without more information. Is the speed constant?