A bullet of mass 0.012 kg and horizontal speed 70 ms -1 strikes a block of wood of mass 0.4 kg and instantly comes to rest w.r.t. block. The block is suspended from the ceiling by means of thin wires. Calculate the height to which the block rises about

Question

A bullet of mass 0.012 kg and horizontal speed 70 ms -1 strikes a block of wood of mass 0.4 kg and instantly comes to rest w.r.t. block. The block is suspended from the ceiling by means of thin wires. Calculate the height to which the block rises about (A) 15 cm (B) 20 cm (C) 25 cm (D) 28 cm

Tardigrade Admin · Accepted Answer

pi=pf (0.012)(70 ms -1)+(0.4 kg ) 0=(0.412) u ⇒ u=2 ms -1 Now, (1/2) m u2=m g h h=(u2/2 g) ≈ 20 cm

Q. A bullet of mass $0.012 k g$ and horizontal speed $70 m s^{- 1}$ strikes a block of wood of mass $0.4 k g$ and instantly comes to rest w.r.t. block. The block is suspended from the ceiling by means of thin wires. Calculate the height to which the block rises about

15 cm

20 cm

25 cm

28 cm

$p_{i} = p_{f}$
$(0.012) (70 m s^{- 1}) + (0.4 k g) 0 = (0.412) u$
$\Rightarrow u = 2 m s^{- 1}$
Now, $\frac{1}{2} m u^{2} = m g h$
$h = \frac{u ^{2}}{2 g} \approx 20 c m$

Q. A bullet of mass 0.012kg and horizontal speed 70ms−1 strikes a block of wood of mass 0.4kg and instantly comes to rest w.r.t. block. The block is suspended from the ceiling by means of thin wires. Calculate the height to which the block rises about