Problems from Week 4

Problem 6-13 from page 187 in Young and Freedman

A baseball is thrown from the roof of a 27.5 m tall building with an initial velocity of magnitude and directed at an angle of above the horizontal.

(a)

What is the speed of the ball just before it strikes the ground? Use energy methods.

(b)

What is the answer for part (a) if the inital velocity is at an angle of below tha horizontal?

Problem 6-78 from page 192 in Young and Freedman

A television set with a mass of 18.2 kg is initially at rest on a horizontally frictionless surface. It is then pulled 2.50m by a horizontal force with magnitude 112 N. Use the work-energy theorem to find its initial speed.

Problem 7-3 from page 219 in Young anf Freedman

The force exerted by the string of a compound bow on an arrow varies as a function of how far back the arrow is pulled. Use the information in the problem and the graph on page 168 in the text to find the speed of an arrow when it leaves the bow.