This instrument is called a spring scale.
The elastic potential energy (Ep) is given by

Data:
Ep = ? (Joule)
k = 20 N/m
x (displacement) = 0.20 m
Solving:




Answer:
6 gallons
Explanation:
At 30 mph, the fuel mileage is 25 mpg.
After 5 hours, the distance traveled is:
30 mi/hr × 5 hr = 150 mi
The amount of gas used is:
150 mi × (1 gal / 25 mi) = 6 gal
Answer:
74.4 kilowatts or 99.8 horsepower
Explanation:
The explanation is in the attachment.