Question

The motor of a four wheeler traveling along a muddy trail generates an average power of 7.05 104 W when moving at a constant speed of 15 m/s. When pulling a log along the trail at the same speed, the engine must generate an average power of 8.15 104 W. What is the tension in the tow rope pulling the log?

Answer 1

Answer:

$F=733.33 N$

Explanation:

Power is the work to make a motion in a determine time also the al the work is the force make in a distance so:

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

$W=F*d$

Replacing

$P=F*\frac{d}{t}$

Knowing that the velocity is:

$v=\frac{d}{t}$

So:

$P=F*v$

Solve to F to determinate the tension that in this case is the force in the rope

$F=\frac{P}{v}$

The power is the total power so:

$P=8.15x10^4W-7.05x10^4W=11x10^3W$

$F=\frac{3kW}{15\frac{m}{s}}=733.33 N$