Question

A tractor drags a 300 lb. concrete block 80 ft. in 120 seconds. Determine the power output of the tractor.

2400 ft-lb/sec
300 ft-lb/sec
200 ft-lb/sec
120 ft-lb/sec

Answer 1

For this case we have that by definition, the mechanical power is given by:

`P = \frac {W} {t}`

Where:

W: It is the work done

t: It's time

For its part:

`W = F * d`

Where:

F: It is the applied force

d: It is the distance traveled

According to the data we have that the drag force of the tractor is
`F = 300lb`, while the distance traveled is
`d = 80ft.`

Substituting:

`P = \frac {300 * 80} {120}\\P = \frac {24000} {120}\\P = 200`

Finally, the power is:

`\frac {200lb-ft} {s}`

Answer:

Option C