A body falling from a vertical height of 10 m pierces through a distance of 1 m in sand. Calculate the average retardation in sand faced by the body. ( g= acceleration due to gravity)
 a)g
 b)9g
 c)100g
 d)1000g

Asked by Sayoni Maiti | 5th Jun, 2014, 01:05: AM

Expert Answer:

When the body falls from the height :
u = 0,
s = 10 m ,
Using the equation v2=u2+2as
v2 = 0 + 2g×10
v = √20g
The velocity when it touches the sand is √20g
So when the body pierces through sand : u = √20g, v=0, s = 1 m
v2=u2+2as
0=(√20g)2+2a
-a = 20g / 2
-a = 10 g
The average retardation in sand faced by the body is 10 g

Answered by Jyothi Nair | 5th Jun, 2014, 10:12: AM