A plastic ruler is held against a rotating bicycle wheel whose speed is gradually being decreased state how does - Physics -

Question

A plastic ruler is held against a rotating bicycle wheel whose
speed is gradually being decreased state how does the pitch of
sound change and why

Vara · Accepted Answer

Pitch is nothing but shrillness of sound, which depends on the
frequency of sound
During the decrease of speed of the bicycle wheel, the
frequency decreases which reduces the pitch of the sound

A plastic ruler is held against a rotating bicycle wheel whose speed is gradually being decreased. state how does the pitch of sound change and why.