(b) Complete the sentence about longitudinal waves.
The vibrations of the air particles are
to the
direction of energy transfer.

(C) A stationary car horn emits a sound wave frequency 400 Hz. The wavelength of the wave is 0.85 m. Calculate the speed of sound.

see below

Explanation:

b ) the vibrations of the air particles are parallel to the direction of energy transfer.

c) use formula

speed = wavelength x frequency

speed = 0.85 x 400

speed = 340 m/s

hope you get it

please mark

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards

answer(20) psi;