Question

Where will the hand of a clock stop if it starts at 12 and makes $\dfrac{1}{2}$ revolution clockwise?

Answer 1

Hint: Clock is in the form of a circle and has overall 1 revolution that is${360^0}$, if a clock starts at 12 and makes half revolution this means that the hand has covered ${180^0}$ in clockwise direction. Use this concept to get the hand's position.

Complete step-by-step answer:

The pictorial representation of the clock shown above the minute hand is initially at 12 (shown by red dotted line).
As we know in a complete revolution the hand of the clock will rotate by 3600.
So in half (1/2) a revolution clock of a hand rotates by $\dfrac{{{{360}^0}}}{2} = {180^0}$.
Now it is given that the hand of the clock is initially at 12 as shown in figure by red dotted line and makes a half a revolution clockwise so the hand of the clock rotates by 1800 as shown in figure.
So the final position of the minute hand of the clock is at 6 as shown in figure.
So the hand of the clock stops at 6.
So this is the required answer.

Note: Diagrammatic representation always helps understanding clock and time based problems. In a clock when the seconds hand completes one revolution of ${360^0}$, then the minute hand is moved one unit in clockwise direction and when a minute hand completes one full revolution of ${360^0}$ then the hour hand moves one unit clockwise. In this way 24 hours of a clock constitute one day.