The first of two identical boxes of mass m is sitting on level ground. The second box is sitting on a ramp that makes a 20° angle with the ground. The normal force of the level ground on the first box is NL; the normal force of the ramp on the second box is NR. Which statement is correct?
a. NR = NL = mg.
b. NL = mg; NR = mg sin 20°.
c. NL = mg; NR = mg cos 20°.
d. NL = mg; NR = -mg cos 20°.
e. NR = -NL = -mg.
C
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