A wave has a frequency of 775 Hz. What is its period?

The period is simply the inverse of the frequency, therefore:

T = 1 / f

T = 1 / 775 Hz

T = 0.001290 s    → possible answer

T = 1.29 × 10⁻³ s   → possible answer

T = 1.29 ms          → possible answer

when earth is in rotational motion around the sun,it displaces from its place.

when a ball is placed on an inclined surface it does both the rotational and circular motion.

explanation:

c)as speed changes, wavelength and frequency change.

everything changes!