Question

solve question number 19

Answer 1

m1=100g=1/10kg
m2=120g=120/1000=3/25kg
u1=6m/s
u2=5m/s
since the objects stick together after collision,
so combined final velocity will be v
by conservation of linear momentum,
m1.u1 + m2.u2=m1.v + m2.v
$\frac{1}{10} \times 6 + \frac{3}{25} \times 5 = (m1 + m2)v \\ \frac{3}{5} + \frac{3}{5 } = (\frac{1}{10} + \frac{3}{25} )v \\ \frac{6}{5} = \frac{11}{50} v \\ \frac{6}{5} \times \frac{50}{11} = v$
60/11 = v
5.5m/s=v

Answer 2

m1=100g=0.1kg
u1=6m/s
m2=120g=0.12kg
u2=5m/s

m1u1+m2u2=(m1+m2)v
v=m1u1+m2u2/m1+m2
= 0.1×6+0.12×5/0.1+0.12
= 0.6+0.6/0.22
= 1.2/0.22
= 5.45m/s