Question

A student slides her 80.0-kg desk across the level floor of her dormitory room a distance 4.00 m at constant speed. If the coefficient of kinetic friction between the desk and the floor is 0.400, how much work did she do

Answer 1

Answer:

Work done is equal to 125.44 J

Explanation:

We have given mass of the student m = 80 kg

Distance moved d = 4 m

Acceleration due to gravity $g=9.8m/sec^2$

Coefficient of kinetic friction $\mu =0.4$

So normal force exerted by student $F=\mu mg=0.4\times 80\times 9.8=313.6N$

We know that work done is equal to multiplication of force and distance

So work done $W=Fd=313.6\times 0.4=125.44J$