What force is necessary to pull a 10 kg sled across a horizontal surface at a constant velocity if the coefficient of kinetic friction between the sled and the ground is 0.25?

Any force greater than 24.5 N

Explanation:

To find the frictional force is the 1st step. this can be found by multiplying the coefficient of friction and the normal force. normal force can be found by multiplying gravity (we will say 9.8 m/s/s) and the mass which is 10. You then multiply the result by the coefficient of friction which is 0.25 and it leads us to an answer to 24.5 N. This means that if you pull with exactly 24.5 N, the sled wouldnt move. So you need a force greater than 24.5 N and we have our answer.

I hope I helped correct me if im wrong

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.