Chapter 2Chapter 2

Part 1 of 2

Example Problems & SolutionsExample Problems & Solutions(useful for homework)

11

• 1 A whale swims due east for a1. A whale swims due east for a distance of 6.9km, turns around and goes due west for 1 8km and finallygoes due west for 1.8km, and finally turns around again and heads 3.7km due east (a) What is the total distancedue east. (a) What is the total distance traveled by the whale? (b) What are the magnitude and direction of themagnitude and direction of the displacement of the whale?

99

• 9. A bicyclist makes a trip that consists of three9. A bicyclist makes a trip that consists of three parts, each in the same direction (due north) along a straight road. During the first part, she rides for 22 minutes at an average speed of 7.2 m/s. During the second part, she rides for 36

i t t d f 5 1 / Fi llminutes at an average speed of 5.1 m/s. Finally, during the third part, she rides for 8.0 minutes at an average speed of 13 m/s (a) how far has thean average speed of 13 m/s. (a) how far has the bicyclist traveled during the entire trip? (b) What is her average velocity for the trip ?g y p

1313

• 13 A motorcycle has a constant13. A motorcycle has a constant acceleration of 2.5 m/s2. Both the velocity and acceleration of the motorcycle point inand acceleration of the motorcycle point in the same direction. How much time is required for the motorcycle to change itsrequired for the motorcycle to change its speed from (a) 21 to 31 m/s, and (b) 51 to 61 m/s?61 m/s?

1515

• 15 A runner accelerates to a velocity of15. A runner accelerates to a velocity of 4.15 m/s due west in 1.5 s. His average acceleration is 0 64 m/s2 also directedacceleration is 0.64 m/s2, also directed due west. What was his velocity when he began accelerating ?began accelerating ?

2121

• 21 A VW Beetle goes from 0 to 60 mi/h21. A VW Beetle goes from 0 to 60 mi/h with an acceleration of +2.35 m/s2. (a) How much time does it take for the BeetleHow much time does it take for the Beetle to reach this speed? (b) A top-fuel dragster can go from 0 to 60 mi/h in 0 6 sdragster can go from 0 to 60 mi/h in 0.6 s. Find the acceleration (in m/s2) of the dragsterdragster.

2727• 27. A speed ramp at an airport is basically a p p p y

large conveyor belt on which you can stand and be moved along. The belt of one ramp moves at a constant speed such that a person who standsa constant speed such that a person who stands still on it leaves the ramp 64 s after getting on. Clifford is in a real hurry, however, and skips the y, , pspeed ramp. Starting from rest with an acceleration of 0.37 m/s2, he covers the same distance as the ramp does but in one fourth thedistance as the ramp does, but in one-fourth the time. What is the speed at which the belt of the ramp is moving ?

3535

• 35 A locomotive is accelerating at 1 635. A locomotive is accelerating at 1.6 m/s2. It passes through a 20-m-wide crossing in a time of 2 4s After thecrossing in a time of 2.4s. After the locomotive leaves the crossing, how much time is required until its speed reaches 32time is required until its speed reaches 32 m/s ?

3737

• 37 The greatest height recorded for a37. The greatest height recorded for a jump into an airbag is 99.4m by stuntman Dan Koko In 1948 he jumped from restDan Koko. In 1948 he jumped from rest from the top of the Vegas World Hotel and Casino He struck the airbag at a speed ofCasino. He struck the airbag at a speed of 39 m/s (88 mi/h). To assess the effects of air resistance determine how fast heair resistance, determine how fast he would have been traveling on impact had air-resistance been absentair resistance been absent.

4141

• 41 A wrecking ball is hanging at rest from41. A wrecking ball is hanging at rest from a crane when suddenly the cable breaks. The time it takes for the ball to fall halfwayThe time it takes for the ball to fall halfway to the ground is 1.2s. Find the time it takes for the ball to fall from rest all the way tofor the ball to fall from rest all the way to the ground.