Between which of the following surfaces would the force of friction be greatest
a. rubber shoes soles on asphalt
b. rubber shoes soles on wet grass
c. rubber shoes soles on artificial turf
d. rubber shoes soles on ice

That would be the corect answer hope this

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j

The sun's gravitational pull is weaker on the planets that are closer to it, i think.