Question

A mass of 10 gm moving with a velocity of 100 cm/s
strikes a pendulum bob of mass 10 gm. The two
masses stick together. The maximum height reached
by the system now is (g = 10 m/s2)
(a) Zero
(b) 5 cm
(c) 2.5 cm
(d) 1.25 cm​

Answer 1

Answer:

Correct answer is (d)

Explanation:

Initially mass 10gm moves

with velocity 100cm/s /Initial

movement =10×100=1000

1000gm×m/sec After collision

system moves with velocity Vsys than

Final momentum = (10+10) × Vsys By applying

the conservation of momentum

1000=20×Vsys

Vsys ==50cm/s If system rises upto height h than

h=v^2sys/2g=50×50/2×1000=2.5/2 =1.25cm

Answer 2

Answer:

d

Explanation:

mu=(m+M)v

=>v = (10×100)÷20

=> v = 50

From conservation of energy,

1/2(m+M)v²=(m+M)gh

=> h= v²/2g ×( m/m+M)²

=> h=

$\frac{ {50}^{2} }{2 \times 10 \times {10}^{2} } ({ \frac{10}{10 + 10} })^{2}$

{ since g is in m/s² changed to cm/s²}

=> h= 1.25 cm