Thread: Hand of a Clock

Through how many radians does the minute hand of a clock turn in 24 minutes?

(1) 0.2π (3) 0.67π
(2) 0.4π (4) 0.8π

MY WORK:

24 minutes/60 minutes = 2/5 = 0.4pi or so I thought.

The correct answer is 0.8pi.

How can this be?

Originally Posted by magentarita

Through how many radians does the minute hand of a clock turn in 24 minutes?

(1) 0.2π (3) 0.67π
(2) 0.4π (4) 0.8π

MY WORK:

24 minutes/60 minutes = 2/5 = 0.4pi or so I thought.

The correct answer is 0.8pi.

How can this be?

You're on the right track. What you did with the 24 min/ 60 min = 2/5 is good...but we have 2/5 of what? The whole circle. A circle has how many degrees [or radians, in this case] in it? Multiply 2/5 to that and see what you get.

--Chris

Originally Posted by Chris L T521

You're on the right track. What you did with the 24 min/ 60 min = 2/5 is good...but we have 2/5 of what? The whole circle. A circle has how many degrees [or radians, in this case] in it? Multiply 2/5 to that and see what you get.

--Chris

Do you mean multiply 2/5 times 360 degress or 2pi?

I multiplied 2/5 by 360 degress and got 144.

What did I do wrong?

Originally Posted by magentarita

Do you mean multiply 2/5 times 360 degress or 2pi?

I multiplied 2/5 by 360 degress and got 144.

What did I do wrong?

In this case, you would multiply by , since we are dealing with choices of angles in radians.

--Chris