Explain the following phenomenon on the basis of Newton's Laws of Motion
a) Falling of building during an earthquake
b) Shattering of car windows due to a bomb blast
c) Cell phone breaks into pieces on falling from a table
d) Finger cuts while suddenly pulling the thread of an air borne kite
e) Guitarists' finger gets injured while sliding it on a guitar string
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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.
2- 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.
4- 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.
5-Same 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 injured.