Question

A football player pushes a sled on a level surface with a weight force of 760 N that acts perpendicular to the surface. The coefficient of kinetic friction between the sled and grass is 0.78 How much work does the football player perform if he pushes the sled and displaces it 10 m. Assume ) the average force performed is equal to the force required to keep the sled in motion and 2) the applied force is paraîlel to the sleds displacement. (3 points) a. b. How much power did the football player produce if he performed the sled push in 3.21 seconds? (2 point)

Answer 1

Answer:

Part a)

W = 5928 J

Part b)

P = 592.8 Watt

Explanation:

As we know that force of friction on the sled is given by

$F_f = \mu F_n$

here we know that

$\mu = 0.78$

also we know that normal force on the sled is counter balanced by the weight of the object

$F_n = mg = 760 N$

now we have

$F_f = (0.78)(760) = 592.8 N$

Now the applied force must be equal to this friction force so that it will start sliding on the grass

now if we push it by 10 m distance then work done to slide it given by

$W = F.d$

$W = (592.8)(10) = 5928 J$

Part B)

Power required to push the sled in 10 s

$Power = \frac{work}{time}$

$Power = \frac{5928}{10} = 592.8 Watt$