There are two ten-yen coins.
One is fixed and another one is rolled and rotated one time so that it might not slide along with the circumference of the fixed ten-yen coin.
How many rotations of the rolled ten-yen coin were made?
One is fixed and another one is rolled and rotated one time so that it might not slide along with the circumference of the fixed ten-yen coin.
How many rotations of the rolled ten-yen coin were made?
Answer
In order to calculate how many rotations of the coin, it becomes (distance by which the center of the circle moved) / (the length of the circumference).
A circle 2cm in diameter rotates around a circle 2cm in diameter for example, the distance by which the center of the circle moved is 4cm × π, and since the length of the circumference is 2cm × π, it can be calculated with two rotations.
Two rotations
Solution
It is easy to understand best to check rotate and check actually.
In order to calculate how many rotations of the coin, it becomes (distance by which the center of the circle moved) / (the length of the circumference).
A circle 2cm in diameter rotates around a circle 2cm in diameter for example, the distance by which the center of the circle moved is 4cm × π, and since the length of the circumference is 2cm × π, it can be calculated with two rotations.
