In case of scissors, blades may be much longer than the handles, because in this case we do not need much mechanical advantage.
(MA – Effort arm/ Load arm).
But, in case of scissors for cutting metals, much higher value of mechanical advantage is needed, to cut the metals easily, so the handles need to be long and blades short. 

Weight of bucket = 6.0 x 10 = 60 N = Load

i) Initially, at point O, the bob is at rest.
When it starts moving towards a, its potential energy starts increasing and at point A it has maximum potential energy and zero kinetic energy. When it starts descending from A, its potential energy starts decreasing and kinetic energy starts increasing. Then at point O it has maximum kinetic energy and minimum potential energy. When it passes its mean position, the potential energy starts increasing and kinetic energy starts decreasing until again at point B, where it has maximum potential energy and zero kinetic energy. 

1 .
Given,
m₁: m₂ = 1: 2
 

2.
According to Newton's second law of motion,
F = ma

When a piece of ice floating in a glass of water melts, the level of water does not change because, the ice has already about 9/10 part of it submerged under water, which already makes a part of volume of water in the glass. So, after melting there is no change in the level of water.