If I am using a tiny inclined plane to do a tiny amount of work. The output is 4 Joules of energy, but I have input 8 Joules of energy. What is my machine's efficiency?
a
50%
2 Newton meters
b

50 Newton meters
2%

i leave the calculator work to you.

7. diameter 4 miles, circumference 4π miles

8. radius 0.2 miles, circumference 0.4π miles

[this is a bad problem because the actual radius of a car on the track is less than 0.2 miles so the answer is less than 0.4π miles]

9. radius 6 feet, circumference 12π feet

10. diameter 14 cm, circumference 14π cm

11. diameter 4.8 feet, circumference 4.8π feet

12/11c

or

12

c

11