Achild rides a bicycle in a circular path with a radius of 2.0 m. the tangential speed of the bicycle is 2.0 m/s. the combined mass of the bicycle and the child is 43 kg. what kind of force provides the centripetal force on the bicycle? a. gravitational force c. air resistance b. friction d. normal force select the best answer from the choices provided

If there was no friction the "centrifugal" force would cause the bike to move outward or away from the circle center. So then friction is holding in it's "orbit" which is the centripetal force.

Hope this helps :)

Your answer is 1.5 hope i  

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