Determine which two bodies are motionless relative to each other and why. A. Earth and Moon

Determine which two bodies are motionless relative to each other and why. A. Earth and Moon B. Clock body and seconds hand C. Cab and body of a truck while driving D. Body and propeller of a flying aircraft

To find the correct answer, consider the nature of the movement of bodies:
a) Earth and moon – the moon revolves around the earth, therefore this answer is incorrect;
b) the watch case and the second hand – the second hand rotates relative to the watch case, so this answer is incorrect;
c) the cab and the body of a truck when driving – while driving, both the cab and the body move in the same direction at the same speed, so we can say that these bodies are motionless relative to each other;
d) the body and propeller of a flying aircraft – during flight, the propeller rotates relative to the body, therefore this answer is incorrect.
Hence, the correct answer is: c – the cab and the body of the truck when driving.