Question

A bullet of mass 20g moving with a speed of 500 m/s strikes a wooden block of mass 1kg and gets embedded in it. Find the speed with which block moves along with the bullet.

Answer 1

Given that,

Mass of bullet(m₁) = 20 g

Initial speed of bullet(u₁) = 500 m/s

Final speed of bullet (v₁) = 0 m/s

Initial speed of the bullet (u₂) = 0 m/s

Mass of wooden block(m₂) = 1 kg

To find,

The speed with which the block moves along with the bullet(v₂) = ?

Before reckoning anythin', we've to check that every given thing is in its SI unit or not.

Here, everythin' is in its SI unit except mass of bullet. So, we've change it into its SI unit.

As we know,

10⁻³ g = 1 kg

20 $\times$ 10⁻³ = 0.02 kg

So, the mass of the bullet is 0.02 kg.

Now, by using law of conservation of mass,

Initial momentum = final momentum

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

(0.02)(500) + (1)(0) = (0.02)(0) +(1)(v₂)

10 + 0 = 0 + v₂

10 = v₂

$\fbox{\bold{\pink{Initial\:speed = 10\:m/s}}}$

Answer 2

Answer:

Hope pic will help you.

Explanation: