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