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Grade 12Algebra

A body is placed on a rough inclined plane of inclination θ. As the angle θ is increased from 0° to 90° the contact force between the block and the plane.
(1) remains constant
(2) first remains constant then decreases
(3) first decreases then increases
(4) first increases then decreases

Profile image of Tanya
9 Years agoGrade 12
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2 Answers

Profile image of Aditya
9 Years ago
The contact force here is friction.
Intitially static friction would be there which would be equal to mgsinθ ,as angle of inclination increases sinθ will increase.It will increase till it reaches its maximum value i.e umgcosθ (max stitic friction) .after that it will remain same i.e umgcosθ but 
θ will continue to increase as a result cosθ would decrease decreasing the friction applied 
Hence correct option is (4)
Profile image of Priya jain
8 Years ago
Option 2