Asmall mass m on a string is rotating without friction in a circle. the string is shortened by pulling it through the axis of rotation without any external torque. what happens to the angular velocity of the object?

a. it decreases.
b. it increases.
c. it remains the same.

The two most prominent wavelengths in the light emitted by a hydrogen discharge lamp are 656(red) and 486 (blue). light from a hydrogen lamp illuminates a diffraction grating with 500 lines per mm, and the light is observed on a screen 1.50 behind the grating. what is the distance between the first-order red and blue fringes?