reaction (1 Viewer)

[jyu]

A 10 kg box on a platform which is inclined at 10 degree to the horizontal. The box is at rest relative to the platform. The platform is lowered with a speed increasing at 1.0 m/s2. What is the magnitude of the reaction force of the platform on the box?

 

[deltaforce22]

This will be my first and last time doing physics. Draw a force diagram (incline plane with normal force begin perpendicular to the incline plane). Remember your downward gravitational pull (mg). We extend the normal force on both directions. Draw a line perpendicularly to this extended normal force (you know which side), and connect it to the gravitational pull. Now you have a right-angled triangle.

tan theta = F/N
F=1, theta = 10.
N = 1/tan10 = cot10

 

[deltaforce22]

Bear in mind, I may be incorrect.

 

[jyu]

the question asked for reaction, not normal reaction.