hw3_sol_sp10

hw3_sol_sp10 - Physics 101 Classical Physics Spring 2010...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Physics 101 Classical Physics Spring 2010 Homework 3 Solutions DUE IN CLASS ON FEBRUARY 4 1. A golfball is driven by a club and travels toward a distant hole. Ne- glecting air resistance, which of the following is true after the ball is hit ( while the golfball is in flight ): (a) There are no forces on the ball (b) There is only a downward force of gravity (c) There is only a horizontal force which makes it travel toward the fence (d) There is both a downward force from gravity and a horizontal force which makes it travel toward the fence (e) Its speed is a constant the entire time 2. A skydiver jumps out of an airplane, and after a short time she travels at a constant velocity (the terminal velocity ) and continues that way until opening her parachute. During this time (from the point she reaches terminal ve- locity until the chute is opened): (a) There is no force exerted by gravity, (b) There must be a force upward balancing the force of gravity , (c) There is a net force downward which causes her to fall at constant velocity, (d) There are no forces acting on her, (e) There is a net force upward which slows her down until she stops 3. In a tug of war, two men pull on a rope with 100-lb forces, in opposite directions. The tension in the rope is: (a) 100 lb , (b) 200 lb, (c) zero, (d) 50 lb, (e) 141 lb Consider the free body diagram of one of the men. There is the 100-lb force acting in say the- x direction and tension acting in the + x direction. There is no acceleration, therefore the magnitude of the tension is the same as the force applied, so the tension is 100-lb. Use the following description to answer the next 2 questions : You hold a 5 kg bowling ball while floating in the vacuum of deep space and then push it away with a force of 10 N. 4. After letting go: (a) The ball keeps going forever at a constant velocity , (b) The ball travels a long time and then eventually slows down, (c) The ball accel- erates continually at 2 m/s 2 , (d) Once you let go, there is no force on it so it cannot move, (e) The velocity of the ball must be 50 m/s There are no forces, so the velocity is constant after letting go. 5. During the time you are pushing the ball: (a) No force is exerted on you, (b) The ball exerts a force on you proportional to its mass, (c) The ball exerts a 10 N force on you , (d) You move in the same direction as the ball, (e) neither you nor the ball move Newtons 3rd law implies that since you applied a force of 10 N to the ball, the ball must exert a force of 10 N on you in the opposite direction. 1 6. As shown in the diagram, two blocks are attached by a string and are accelerating downward with an acceleration of g/ 3 . The block on top is attached by another string to some other unknown object, as shown in the diagram....
View Full Document

Page1 / 8

hw3_sol_sp10 - Physics 101 Classical Physics Spring 2010...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online