Answers to Chapter Ten Questions

1)      After 1 second it is going 32 ft/s

After 2 seconds it is going 64 ft/s

After 3 seconds it is going 96 ft/s

After 4 seconds it is going 128 ft/s

After 5 seconds it is going 160 ft/s

2)      Zero acceleration, you are not going anyplace!

3)      Zero net force, no acceleration means there is no net force.

4)      The scale in the rocket reads Chuck’s weight.

5)      The scale is pushing up on Chuck causing him to accelerate at 32 ft/s2, the force required to cause that much acceleration is Chuck’s mass times 32 ft/s2, which is the same as his weight.  Thus the scale in the accelerating rocket reads exactly the same value as it did for the stationary rocket on Earth.

6)      The coasting rocket has zero acceleration.  So Chuck has no acceleration which means the scale is no longer pushing up on Chuck.  The scale reads zero.

7)      24 hours times 60 minutes in each hour times 60 seconds in each minute = 86400 seconds.

8)      Speed = 32 ft/s2 times 86400 seconds = 2,764,800 ft/s  = 1,885,091 mph!

9)      Speed/Velocity of Light = 0.0027648, less than 0.3 % of the speed of light!

10)   

TRocket

TEarth

XEarth

VStart

VEnd

VAverage

ΔTEarth

ΔXEarth

0

0

0

0

0.00276

0.00138

1

0.00138

1

1

0.00138

0.00276

0.00552

0.00414

1.000004

0.00414

2

2.000004

0.00552

0.00552

0.00828

0.0069

1.000015

0.0069

11)  4,290,958 days have passed on Earth which is 11,756 years!

12)  4,290,596 light-days from Earth which is 11,755 light-years!

13)  The rocket reaches a distance of 23,510 light-years from Earth before beginning its trip back home.  That is about ¼ the diameter of the Milky Way and only about 1 % of the distance to the Andromeda Galaxy, our nearest neighbor major galaxy!

14)  23,512 years have passed on Earth while the rocket traveled for 40 years!

15)  This for you to do if you have not yet done it!

16)  Rockets move by pushing stuff out one end causing the rocket to move in the opposite direction to conserve momentum.

17)  3 x 1022 kilograms!!

18)  As described in the chapter, a shell of thickness 6.7 miles would have to be scraped off the surface of the Earth in order for a rocket to have enough fuel to accelerate at 32 ft/s2 for 40 years.