Answer:
50
Explanation:
The mechanical advantage of a machine is given by
where
is the output force
is the input force
For the crowbar in this problem,
is the force in input applied by the worker
is the force that the machine must apply in output to overcome the resistance of the window and to open it
Substituting into the equation, we find
Mg = 6.2 x 9.81 = 60.822
This is also normal force.
Coefficient of friction times normal force is the force due to friction:
60.822 x 0.24 = 14.6N
F = MA so F(your force) - F(friction) = 6.2 x 0.5
= 3.1
Your answer is 3.1+ 14.6
I hope this is correct though I might be wrong.
While the box slides down the horizontal surface, it is using kinetic energy. and while it slides down the wind is going against it... kinda like when a space shuttle goes into the Earth's atmoshphere.