Answer:
47.04N
Explanation:
The force applied by the deranged Rugby player who wish to burn excess energy by venting it on a box around is house is as follows;
First coefficient of kinetic friction,μk
μk= Kinetic Frictional Force/Normal reaction
The normal reaction is a vertical force acting opposite to the weight of the object
Hence Normal reaction=mass of object × acceleration of free fall due to gravity (g).
Let g= 9.8m/s
Normal reaction= 15 ×9.8 =147N
Hence kinetic Frictional force = μk×Normal reaction.
0.3×147=44.1N
Now the force applied by the player overcomes the kinetic Frictional force and the object accelerates moving a distance of 5m.
Now the force the object acquires to move a distance of 5m is given by Newton's second law,F =m×a
Where m is mass of object , a is acceleration of object.
Now by looking at the formula above, we don't know acceleration.
Let's calculate the acceleration .
From Newton law of motion.
V2 = U2 + 2aS
U = 0 { the body starts from rest so initial velocity is zero}
S = 5m{ distance of object}
a = ?{ acceleration of object}
Substituting the known values we have;
1.4^2 =0+ 2× a×5
1.96 = 10a
a = 1.96/10= 0.196m/S2
Hence Force of the object =15×0.196= 2.94N
Hence the force applied by the Rugby player is the force required to overcome the frictional force plus that required to accelerate the object
44.1+2.94= 47.04N
Note: I have converted velocity in cm/s to m/s by dividing by 100
