Question

A gun fires N bullets per minute. The mass of each bullet is 10g and every bullet travels With a speed of 600m/s. If the power delivered by the gun is 9000W,the value of N is:

• A. 300
• B. 400
• C. 360
• D. 420
• E. 250

Answer 1

Answer: (A)

300

Answer 2

The correct option is (A): 300
The formula for Power(P) is:
$P = \frac{W}{t}$
Where W is the work done and t is the time taken.
The work done in this case is the kinetic energy KE of one bullet, which is given by:
$KE = \frac{1}{2} m v^2$
Where m is the mass of the bullet and v is its velocity.
Substituting the given values:
$KE = \frac{1}{2} \times 0.01 \, \text{kg} \times (600 \, \text{m/s})^2$
$KE = 1800 \, \text{J}$
Now, since the power P is given as 9000W, we can rewrite the power formula as:
$9000 = \frac{1800 \times N}{60}$
Where N is the number of bullets fired per minute.
$9000 \times 60 = 1800 \times N$
$540000 = 1800N$
$N = \frac{540000}{1800}$
$N = 300$
Thus, the number of bullets fired per minute is N =300