Question

A gun fires bullets of mass 40 g horizontally towards a square platform of area 50 sq. cm. Pressure registered by a device connected to the platform is 2.88 × 10⁴ pa. If speed of bullets is 1200 m/s. How many bullets hit the platform?

Options

• 3 bullets per second 

• 3 bullets in 2 seconds

•  6 bullets per second

•  2 bullets in 0.5 seconds

Answer 1

3 bullets in 2 seconds

Explanation:

F = PA = 2.88 × 10⁴ × 50 × 10^–4 = 144N

F = `(Delta"P")/(Delta"t")` ⇒ 144

= `(Delta"P")/1` ⇒ ΔP = 144

Now momentum imparted by particle

P = 2 × 1200 × 40 × 10^–3

∴ No of particles = `144/(2xx1200xx40xx10^-3)`

= 1.5 per second

= 3 in 2 seconds