- #1

cy19861126

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Thanks for the patience for reading the problem, my work so far is:

a) For the y component,

Fy = ma, since a is 0...

Ty+Ny-Wy = 0

80sin25+Ny-25*9.8 = 0

Ny = 211N

fx(friction) = uNy = 0.300*211N = 63.4

For the x component,

Fx = ma

Tx-fx = ma

80cos25-fx = 25a

72.5-63.4 = 25a

a = 0.364m/s2. This is my answer, but I'm not sure whether it's right or not, but the problem begins in part b.

b) For the y component

Fy = ma

Ny + Ty + Wy = 0

Ny + 80sin25-245cos10 = 0

Ny = 207.5

f = uN = 0.300 * 207.5 = 62.2N

For the x component.

F = ma

Tx-Wx-fx = ma

80cos25 - 245sin10-62.2 = 25a

a = -1.29m/s2

I do not believe the acceleration to be negative in the incline. If so, the student cannot pull the box up and the problem cannot have taken place. I checked my work for like 10 times. Can someone check what I did wrong? Thanks