hw1 Physics 7. Homework # 4 Due: 4/26 1)      So, if gravity is a universal force and the sun is then pulling on us, and if the sun is much larger and more massive than the Earth, why are we not pulled to the sun and burn? a)      Because gravity is woo weak in space b)      Because there is absolutely no gravity in space c)      Because of friction d)     Because the Earth has some velocity, and so it moves in a direction perpendicular to the line to the Sun, even as the sun attracts it. As a result the Earth moves in orbit. 2)      According to Newtonłs 3rd law, if a boxer hits his opponent very hard, he should experience and equal and opposite effect. Why then the one who hits is not pushed backwards? a)      Because the boxer is too massive. b)      Because Newtonłs 3rd law is not valid for living things c)      He is pushed back, but the motion is countered by the friction between his feet and the floor d)     Because gravity balances the effect 3)      As long as a current is flowing through an electromagnet, a)      It is impossible to distinguish its effects form those produced by a permanent magnet b)      It appears to behave like a real magnet but this is only at large distances from it; close by it behaves like a series of charges c)      It behaves like a magnet only near-by, farther away it resembles a collection of positive and negative charges d)     It creates a magnet with only a north pole 4)      Give two distinguishing characteristics of waves. ? a)      They do not go around objects and cannot be localized b)      They go around objects and can interfere c)      They interfere only if they are water waves, light waves do not interfere d)     They can be put in orbit around any object