A 60-kg man is one-fourth of the way up a 10-m ladder that is resting against a smooth, frictionless wall. If the ladder has a mass of 25 kg and it makes an angle of 60° with the ground, find the force of friction of the ground on the foot of the ladder.
a. 1.4E+1 N
b. 1.6E+2 N
c. 2.4E+2 N
d. 2.7E+2 N
e. 4.2E+3 N