Question

Draw a free body diagram for block 1 and block 2 indicating forces and respective directions and explain which of these two forces are stronger: Tension and Friction? (No need to calculate, just explain why you chose your answer).

Mass 1 = 2.85 kg Kinetic Friction Coefficient = 0.552 Mass 2 = 4.75 kg 40 degrees

Answer 1

FBD of m2

m2 a = m2 g - T

T = m2 g - m2 a... (i)

FBD of m1

m1 a = T - u m1 g cos x - m1 g sin x

from (i)

m1 a = m2 g - m2 a - u m1 g cos x - m1 g sin x

a ( 4.75 + 2.85) = 4.75* 9.8 - 0.552* 2.85* 9.8 cos 40 - 2.85* 9.8 sin 40

a = 2.209 m/s^2

putting in (i)

T =4.75* ( 9.8 - 2.209)

T = 36.06 N

now,

frictional force

f = u m1 g cos x = 0.552* 2.85* 9.8 cos 40

f = 11.81 N

hence, T > f