Answer on Question #44606, Physics, Mechanics | Kinematics | Dynamics
a block(8.5kg) is fixed in aa frictionless incline plane by a rope. the angle θ=30 . what is the normal force acting on the block.
Solution.

From 1st Newton's law:
mg+N+F=0
Where N is the normal force acting on the block.
In projections:
OX: mg⋅sin(θ)=F
OY: mg⋅cos(θ)=N
So: N=mg⋅cos(θ)
Numerically:
N=8.5kg⋅9.8s2m⋅cos(30∘)≈72.14N
Answer: N≈72.14 N
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