A39.7 n object is in free fall. what is the magnitude of the net force which acts on the object? answer in units of n.

If there is no air resistance, the value would still be the same. So therefore, the answer is 39.7 N.
Supposing that there is an air resistance of 19.8 N.With a 19.8 N air resistance: ∑F = 39.7 N - 19.8 N = 19.9 N would be the net force. The important point here is that the force of gravity equivalent the weight of the object.

v= 20.8 m/s

Explanation:

Assuming no other forces acting on the ball, from the instant that is thrown vertically downward, it's only accelerated by gravity, in this same direction, with a constant value of -9.8 m/s2  (assuming the ground level as the zero reference level and the upward direction as positive).In order to find the final speed 2.00 s after being thrown, we can apply the definition of acceleration, rearranging terms, as follows:

       

We have the value of t, but since the ball was thrown, this means that it had an initial non-zero velocity v₀.Due to we know the value of the vertical displacement also, we can use the following kinematic equation in order to find the initial velocity v₀:

       

where Δy = yf - y₀ = 15.4 m - 37.4 m = -22 m (3)Replacing by the values of Δy, a and t, we can solve for v₀ as follows:

       

Replacing (4) , and the values of g and t in (1) we can find the value that we are looking for, vf:

       

Therefore, the speed of the ball (the magnitude of the velocity) as it passes the top of the window is 20.8 m/s.