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 
; the normal force of the ramp on the second box is 
. Which statement is correct?
A.
= = mg.B.
= mg; = mg sin 20°.C.
= mg; = mg cos 20°.D.
= mg; = ?mg cos 20°.E.
= ? = ?mg.Answer: C
Physics & Space Science
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