What is the weight of body on inclined plane? If weighing machine is kept on inclined plane,and a person measures his weight on the scale,will he get less or more weight on scale
Acc to me mg cos theta will be shown in the weighing scale, so if angle is increased the weight would decrease.
Please take care that its a concrete inclined plane and a man is standing on weighing machine kept on inclined plane.
Dear fellowsplease tell if my reasoning is right and otherwise also.
 A: You reasoning is correct. It helps to look at the limit cases. If the inclination is close to zero, cos of the angle is one, so you will see mg as expected. If the inclination is 90 degree, there should not be any force of the scale because the man and the inclined surface are just standing next to each other. So the scale should read zero. cos 90 is zero. So everything is mathematically consistent.
A: Interestingly enough, if one stands on an inclined plane, they must lean back to balance, thereby putting 1 G on the ground contact point.
If they remain upright and balance their weight with a cane, then the weight on their feet is cosine ramp angle.
If they are moving down the ramp in a steady state (constant v), then the g force at their feet is cosine ramp angle.
For more please see link in comment above provided by Buraian.
A: If scales only measure normal force through them, they will show decreased weight. If scales measure all the force going through them they will show the same weight as on the floor.
The friction: If person stands on an incline, and he is not sliding, even with part of the gravity trying to make him slide, something is holding him. It is friction. Friction force is directed parallel to the inclined surface. It 'pulls' the human up the incline. This exactly cancels out sideways force that would make a person slide down. This also makes total force on a scale to be exactly like normal on a flat floor. This makes normal force less. Normal means perpendicular to a plane.
Critical case: if scales are glued to tje wall, and a person is glued to the scale, and scales are designed to measure only normal force, but have strong case that prevents sideways movement - scales will show 0 force, and all the weight will be transfered through the shell that prevents sliding.
Real scales usually have tenso sensor, elongation sensor. They have metal bar with drilled holes, sensor measures the bending of the bar. Depending where person is glued onto the scale on the wall, person will bend the scale plate, bending the bar as well. If person is glued on top of the bar, bar will bend outward, showing negative force. Real scales will show 0 instead. If person is glued below the bar, there will be minimal amount of bending and scales will show 0. If person is glued on the inside of scales, above the bar, bar will bend as if load is applied. And will show large load. Getting larger as larger leverage is used, like more glue. If person is glued from inside the scale, below the bar, scales will also show no force and almost no bending will be present.
