Mechanical Waves and Sound

What is the relationship between the frequency ($f$) and period ($T$) of a wave?

A wave has a frequency of 5 Hz and a wavelength of 2 meters. What is the velocity of the wave?

A wave travels from one medium to another, where its velocity increases by a factor of 2. If the initial wavelength was $\lambda$, what is the new wavelength?

Two waves with the same amplitude meet in phase. What is the result of this interference?

Two waves with amplitudes of 3 m and 4 m interfere constructively. What is the resulting amplitude?

For constructive interference, what is the path length difference between two waves, in terms of wavelength $\lambda$?

In a standing wave, where are the points of maximum displacement located?

A string fixed at both ends has a standing wave with 3 antinodes. What is the relationship between the length $L$ of the string and the wavelength $\lambda$ of the standing wave?