Homework Set 1

HOMEWORK SET 1
Problems and Conceptual Exercises

1. The movie Spiderman brought in $114,000,000 during its opening weekend. Express this amount in scientific notation.
2. The speed of light is 299,792,458 m/s. Express that in scientific notation, and round to 3 significant figures.
3. If acceleration is expressed as, a = 2xtp, then find out what the number “p” is (the exponent of t). Here, x is distance, t is time.
4. The irrational number p = 3.14159265358979…..Round this to seven significant figures
5. The largest blue whale observed was 108 feet long. Find that in meters.
6. Woody the Woodpecker can accelerate its beak to 98 m/s2. Express that in feet per square second, ft/s2.
7. Antonio just won a $12 million pay out from the local state lottery.
a. If he took all $12 million in quarters, how much mass is that?
b. If he took it all in $1 bills, how heavy, in mass, is that?
8. Take a look at the diagram below. Imagine leaving your house and walking east to the Library. When you are finished, you turn around and walk west to the local Park. The distance from your house to the park is 0.75 miles and the Library is another 0.6 miles east of that.
a. How far did you walk, i.e., total distanced from your house to the Library to the Park?
b. What was your displacement, i.e., net distance from your house to the Park?
H______E_____G
House …………………Park…………………Library
0.75 mi 0.60 mi
9. The golfer, below, stands 10 meters to the west of the hole, and sinks the ball in two putts. His first putt misses the hole and travels 2.5 meters further east of the hole. On his second putt, the ball travels 2.5 meters west and falls in.
a. How far did the ball travel overall?
b. What was the total displacement of the ball?
m________w__r
Golfer dude………………hole…….where ball stops after first putt
10 m 2.5 m
10. The Olympic record for the 200 meter dash was 19.75 seconds in 1988. How fast is that in meters per second? Miles per hour?
11. Radio waves are light waves and thus travel at the speed of light, about 186,000 miles per second. How much time would it take for a radio wave to travel from Earth to the Moon and back? (The Moon is, on average, about 240,000 miles from Earth).
12. A dog named Fido runs back and forth between Jack and Jill, as seen in the diagram below. However, Jack is walking towards Jill at 1.3 m/s while Jill is walking towards Jack at 1.3 m/s. If Fido begins to run when Jack and Jill are 10.0 meters apart, and if he travels at 3.0 m/s, how far will Fido travel when Jack and Jill crash into each other?
a a Z

13. Assume that the brakes in your car create a constant deceleration of 4.2 m/s2 regardless of how fast you are driving. If you double your driving speed from 16 m/s to 32 m/s
a. does the time required to stop increase by a factor of two or a factor of four? Explain.
b. Verify your answer by calculating the stopping times for the initial speeds of 16 m/s
c. Verify your answer by calculating the stopping times for the initial speeds of 32 m/s.
14. Approximate 0.1% of the bacteria in the intestine are E coli. These bacteria have been observed to move with speeds of up to 15 m/s (microns per second) and max accelerations of 166 m/s2. Suppose an E coli bacterium in your intestine starts at rest and accelerates at 156 m/s2.
a. How much time is required for the bacterium to reach a speed of 12 m/s?
b. How much distance is required for the bacterium to reach a speed of 12 m/s?
15. A model rocket rises with constant acceleration to a height of 3.2 m, at which point its speed is 26.0 m/s.
a. How much time does it take for the rocket to reach this height?
b. What was the magnitude of the rocket’s acceleration?
c. Find the height and speed of the rocket 0.10 s after launch.
16. A bicyclist named Bob is finishing his repair of a flat tire when a friend named Bill rides by with a constant speed of 3.5 m/s. Two seconds (2.0 s) bob hops on his bike and accelerates at 2.4 m/s2 until he catches up with Bill. b
a. How much time does it take for Bob to catch up with Bill?
b. How far has Bob traveled in this time?
c.What is Bob’s speed when catches up with Bill?
17. Review the image of the car falling off a cliff. The driver says, “Let’s see if we can go from zero to sixty in three seconds.” Prove the driver right or wrong.