HURRY An ultrasound tech is trying to identify an object, but the screen of the machine is broken. Which statement best describes this situation?

The generated sound wave will not be able to reflect off of the object.
The sound wave will not be generated, so there will be no echoes received.
The echoes will be made but will not be able to be received by the machine.
The machine will not be able to process the received echoes into images.

The frequency of vibrations of a vibrating violin string is given by f = 1 2l t ρ where l is the length of the string, t is its tension, and ρ is its linear density.† (a) find the rate of change of the frequency with respect to the following. (i) the length (when t and ρ are constant) (ii) the tension (when l and ρ are constant) (iii) the linear density (when l and t are constant) (b) the pitch of a note (how high or low the note sounds) is determined by the frequency f. (the higher the frequency, the higher the pitch.) use the signs of the derivatives in part (a) to determine what happens to the pitch of a note for the following. (i) when the effective length of a string is decreased by placing a finger on the string so a shorter portion of the string vibrates df dl 0 and l is ⇒ f is ⇒ (ii) when the tension is increased by turning a tuning peg df dt 0 and t is ⇒ f is ⇒ (iii) when the linear density is increased by switching to another string df dρ 0 and ρ is ⇒ f is ⇒

What is friction? how does it affect the motion of an object?

Wavelength of 125 meters is moving at a speed of 10 m/s. what is it's frequency?