A uniform metering scale of mass 2kg is suspended from one end. If it is displaced through an angle 60 from the vertical the increase in its potential energy is
1)4.9J
2)9.8 J
3)3.5J
4)90J
Dear student,
The length of the stick is 1 metre so its centre of mass is at 0.5 metre from either end.
Now, on displacement of 600 of the stick the COM would rise -----
0.5 - 0.5cos600 = 0.5 x (1 - 0.5) = 0.25metre
Thus new location of COM is 0.25 m above the old location. and therefore the increase in PE would be,
2 kg x 9.8ms-2 x 0.25 m = 4.9Joules
Regards
The length of the stick is 1 metre so its centre of mass is at 0.5 metre from either end.
Now, on displacement of 600 of the stick the COM would rise -----
0.5 - 0.5cos600 = 0.5 x (1 - 0.5) = 0.25metre
Thus new location of COM is 0.25 m above the old location. and therefore the increase in PE would be,
2 kg x 9.8ms-2 x 0.25 m = 4.9Joules
Regards