1.) A 25 kg crate is pulled by a force T = 100 N at a 30o angle to the horizonta

Question

1.) A 25 kg crate is pulled by a force T = 100 N at a 30o angle to the horizontal as shown below. It is pulled at a constant velocity for 8 meters in a straight line. What work is done by the pulling force T?

a.) 89 J b.) 81.6 J c.) 800 J d.) 1960 J e.) 693 J

2.) For the 25 kg crate described in question 10, what work was done by friction?

a.) -800 J b.) -693 J c.) -89 J d.) Can't tell without knowing the coefficient of friction. e.) -1960 J

3.) For the crate described in question 10, what work is done by gravity in pulling the crate across the floor?

a.) 245 J b.) 1960 J c.) 693 J d.) 800 J e.) 0 J

Explanation / Answer

1) Work done by pulling force, WT = T.d = T * d * cos30o = 100 * 8 * cos30o = 693 J

2) Since the crate is moving, friction is kinetic. We cant calculate work done by friction without knowing the coeficient of kinetic friction.

3) Since no movement takes place in the direction of gravity, work done is zero.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.