A disc of mass 100 g is kept floating horizontally in air by firing bullets

A disc of mass 100 g is kept floating horizontally in air by firing bullets, each of mass 5g with the same velocity at the same rate of 10 bullets/s.The bullets rebound with the same speed in opposite direction,the velocity of each bullet at the time of impact is

Options

(a) 196 cms⁻¹
(b) 9.8 cms⁻¹
(c) 98 cms⁻¹
(d) 980 cm⁻¹

Correct Answer:

980 cm⁻¹

Explanation:

Rate of change in momentum of the bullets balances weight of the plate

2m’vn = mg
.·. v = mg/2m’n = (100 x 980)/(2 x 5 x 10)
= 980 cm⁻¹

admin:

Related Questions

  1. A bar magnet has a coercivity of 4×10³ Am⁻¹. It is placed inside a solenoid
  2. The temperature coefficient of resistance of an alloy used for making resistor is
  3. A boat which has a speed of 5 kmh⁻¹ in still water crosses river of width 1 km long
  4. Activity of a radioactive sample decreases to (1/3)rd of its original value
  5. A stationary particle explodes into two particles of masses m₁ and m₂ which move