A crate of mass 9.2 kg is pulled up a rough incline with an initial speed of 1.42 m/s. The pulling force is 94 N parallel to the incline, which makes an angle of 19.6° with the horizontal. The coefficient of kinetic friction is 0.400, and the crate is pulled 4.92 m. (a) How much work is done by the gravitational force on the crate?.

W = - 148.8 J

Explanation:

given,

mass = 9.2 kg

initial speed = 1.42 m/s

pulling force = 94 N

angle θ = 19.6°

coefficient of kinetic friction = 0.400

the crate is pulled = 4.92 m

to calculate of work done by the gravitation force

gravitation force

W = (m g sin θ) x

W = 9.2 * (-9.8) * sin 19.6° * 4.92

W = - 148.8 J

Work done by the gravitation force is taken as negative because gravitation force act opposite to the force applied.