Power

Here : Number of bullets n = 360, Time = 1 minute =60 sec, Mass of bullet = Velocity v = 360 km/hr Now power of gun is given by = 600 watt

The power of the gun can be calculated using the formula for the power delivered to the bullets: The work done per bullet is equal to the kinetic energy given by: Where: - is the mass of each bullet, - is the velocity of the bullet. Given: - , - , - The number of bullets fired per minute is 120, which means in . Now, calculate the work done per bullet: Next, calculate the total work done in 60 seconds (since 120 bullets are fired in 1 minute): Now, calculate the power: Thus, the power of the gun is .

The power output of the heating unit is given by the formula: where: - is the power output, - is the voltage across the heating unit, - is the resistance of the heating unit.
Step 1: Calculate the resistance of the heating unit
For the heating unit designed to operate at 500 W on a 400 V line, we use the formula to find the resistance: Solving for :
Step 2: Calculate the power output at the reduced voltage
Now, if the voltage drops to 160 V, the new power output is: Substituting the value of :
Step 3: Calculate the percentage drop in power
The percentage drop in power is given by: Thus, the percentage drop in heat output is 84%, and the correct answer is option (C).