1- During an earthquake, buildings are suddenly forced to move very
quickly that it suffers damage. Newton's second law of motion F=(mv-mu) /
t or F=ma is applied here.
During an earthquake, the speed at which
both the ground and building are moving will reach some maximum. The
more quickly they reach this maximum, the greater their acceleration.
The glasses of a car windows shatter due to a bomb blast because as
the bomb blasts it compresses the air surrounding it to large pressure
and when this wave hits the glass surface with a high speed it applies a
great force on the glasses and breaks them. Here, Newton's second law
(F=dP/dt=mv-mu/t ) is applied.
3- When a cell phone falls on the
ground from the table with a speed. Its momentum becomes zero in a very
short time interval. So, then applying Newton's second law
(F=dP/dt=mv-mu/t ), a great force is exerted on it. Thus, it breaks.
While suddenly pulling the thread, the momentum is reduced to zero in a
very short interval of time. So, then applying Newton's second law
(F=dP/dt=mv-mu/t ), a great force is exerted on finger and it hurts.
as (4). Also the string is very thin having less cross sectional area.
Thus, P=F/A, a high pressure is applied and guitarist's finger gets