Picture a grain of rice weighing 25 mg, 6mm long, rolling off a one meter long slope at a 45 degree angle at the height 1.5 meters above the...

Assumptions

Grain is uniform and the centre of gravity is located 3mm from the edge of grain

Centre of gravity of grain is at point A when starts moving

There is no friction in the ramp and movement starts from rest

Only gravitational forces act on grain

Acceleration in the direction of movement = gcos45

When passing a point at 150mm grain has to travel 3+150 = 153mm to completely pass the point.

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Assumptions

Grain is uniform and the centre of gravity is located 3mm from the edge of grain

Centre of gravity of grain is at point A when starts moving

There is no friction in the ramp and movement starts from rest

Only gravitational forces act on grain

Acceleration in the direction of movement = gcos45

When passing a point at 150mm grain has to travel 3+150 = 153mm to completely pass the point.

Using equation of motion in the direction of travel;

`S = ut+1/2at^2`

`153 = 0+1/2*gcos45*t^2`

`t = 6.64s`

So the grain will take 6.64s to pass the point.