During a football workout, two linemen are pushing the coach on the sled. The combined mass of the sled and the coach is 300 kg. The coefficient of friction between
the sled and the grass is 0.800. The sled accelerates at the rate of 0.580 m/s^2.
Determine the force applied to the sled by the lineman.

F_{players} = 2528.4[N]

Explanation:

To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body must be equal to the product of mass by acceleration.

On the sled act two forces, the force of friction and The Force executed by the football players.

The movement of the football players will be taken as positive, while the friction will be taken as negative, since it is opposed to the movement of the sled.

ΣF = m*a

where:

F = force [N]

m = mass [kg]

a = acceleration = 0.580 [m/s²]

The friction force is defected as the coefficient of friction by the normal force, the normal force on a horizontal surface can be calculated as the product of mass by gravitational acceleration.

Now we can calculate the force exerted by the players.

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.