3. A wooden block is at rest on a wooden inclined plane. As the angle the plane makes with the
horizontal is increased, the magnitude of the
force of static friction between the block and
the plane
(1) decreases
(2) increases
(3) remains the same

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.

answer is slate

hope this