A machine gun fires n bullets per second, each of mass m with velocity v. The force on the gun is MCQ with Answer and Explanation

Explanation:
g is slightly higher at poles (9.83 m/s²) than equator (9.78 m/s²) due to Earth's rotation (centrifugal effect) and equatorial bulge. Weight = mg, so weight increases slightly. Mass constant.

Explanation:
2.50 has three significant digits. Trailing zero after decimal significant because least count 0.01.

Explanation:
Bimetallic strip consists of two metals with different coefficients of linear expansion. On heating, one expands more, causing bending. Used in thermostats, fire alarms. Expansion difference causes curvature.