Help Session (Chapter 4)

Sunday Mar 13 (Bldg 6 / Rm 125)

These are the problems we will tackle in the help session. Please print them!

Problem 1

(Bureaucracy)

An employee needs to get a paper signed. So he walks 100 m northeast to office “A”, which sends him to office “B” located 50 m to the east of office “A”. Office “B” asks him to go to the bank and buy a coupon and then return to office “B”. The path between office B and the bank is a semi-circle of radius 50 m. When he returns to office “B” again they send him to a third office “C” located 200 m at an angle 30 south of east. The employee covers the whole trip in 2 hours. What are (a) his average velocity and (b) his average speed?

Problem 2

An astronaut floats in space from point A to point B in 1 minute. If the (x, y, z) coordinates, in meter, of A and B are (2, 3, -4) and (-3, 2, 4), respectfully, find his average velocity?

Problem 3

A boy kicks a ball from the top of a 20-m high building with initial speed of 10 m/s at 30º above the horizontal. The ball lands somewhere at the roof of another building 10 m high. What is the time of flight of the ball?

Problem 4

A boy kicks a ball from the top of a 20-m high building with initial speed of 10 m/s at 30º above the horizontal. The ball lands somewhere at the roof of another building 10 m high. Where will the ball land?

Problem 5

A bird is flying due east at a speed of 2 m/s (with respect to wind). If the wind is blowing in a northeasterly direction at a speed of 1 m/s (with respect to the ground), what is the velocity of the bird (with respect to the ground)?