Question

A skier of mass 72 kg is pulled up a slope by a motor-driven cable. a. how much work is required to pull him 75 m up a 30 degree slope (assumed frictionless) at a constant speed of 3.4 m/s

Answer 1

Answer: $26.460\times 10^3\ J$

Explanation:

Given the mass of skier m=72 kg

distance traveled d=75 m

constant speed v=3.4 m/s

If speed is constant  then there must no force acting in the direction of motion

i.e. tension force must be equal to the component of weight

$T=mg\sin 30^{\circ}$

Work done is given by

$\Rightarrow W=F\cdot d=Td\cos 0^{\circ}\\\Rightarrow W=mg\sin 30^{\circ} d=72\times 9.8\times 0.5\times 75\\\Rightarrow W=26.460\times 10^3\ J$