Answer:
The average thrust of the sand on the body of mass 2kg will be 1980N.
Explanation:
The values given in the question are,
Mass(m)=2Kg ,
Height(h)=60m,
Depth into the sand(s)=0.6m
Just before hitting the ground
[tex]v^{2}[/tex]=[tex]u^{2}[/tex]+2gh=0+2 × 9.8 × 60 (∵[tex]u^{2}[/tex]=0 as it is dropped from rest)
[tex]v^{2}[/tex]=1176m/s
When the stone penetrates the sound
[tex]v^{2}[/tex]=[tex]u^{2}[/tex]+2as
0=[tex]u^{2}[/tex]+2 × a × 0.6 (∵[tex]v^{2}[/tex]=0 as it is brought to rest )
-1176=1.2a
a=-1176[tex]/[/tex]1.2=-980m[tex]s^{-2}[/tex]
Here (-) indicates the direction of acceleration.
Average thrust on the sand(F)=m(g+a) (∵gravitational force and frictional force are acting in opposite directions)
F=2(9.8+980)=2 × 989.8=1979.6N≈1980N
Hence, the average thrust of the sand on 2kg mass will be 1980N.