Question

a cricket ball of mass 120 g moving with a speed of 100 m/ s pierces through a sack of sand 10 cm thick and comes out with a velocity of 60m/s.determine the average force exerted by the sand on ball. .

Answer 1

We have initial velocity(u)=10m/s , final velocity(v)=60m/s , and distance(s)=10cm =1/10m , mass(m)=120g=12/100kg

Accelaration(a)=?

According to equation of motion, we have v2= u2 +2as

=602= 102+2*a*1/10

= 3600 =100+ a/5

=3500=a/5 =Accelaration(a) = 17500m/s2

Now force(f) =mass(m) * accelaration(a)

=f =12/100*17500

= Force exerted by ball =2100N

According to 3rd law of motion, Force exerted by ball= Force exerted by sand

= Sand exerts force of 2100N