Class 11 NEET Physics Work, Energy and Power Questions

Mass of metal ball = 2kg;
Speed of metal ball (v1)=36km∕h=10m∕s andmass of stationary ball =3. kg.
Applying law of conservation of momentum,
m1v1+m2v2 =(m1+m2)v
or, v=

m1v1+m2v2

m1+m2

=

(2×10)+(3×0)

2+3

=

20

5

Therefore loss of energy =[

1

2

m1v12+

1

2

m2v22] −

1

2

×(m1+m2)v2
=[

1

2

×2×(10)2+

1

2

×3(0)2] −

1

2

×(2+3)×(4)2
=100−40=60J