Acrate 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.

the answer is b, have negligible mass