A bat can detect small objects, such as an insect, whose size is approximately e

Question

A bat can detect small objects, such as an insect, whose size is approximately equal to one wavelength of the sound the bat makes. If bats emit a chirp at a frequency of 4.89 104 Hz, and if the speed of sound in air is 343 m/s, what is the smallest insect a bat can detect? mm

An ethernet cable is 3.90 m long and has a mass of 0.195 kg. A transverse pulse is produced by plucking one end of the taut cable. The pulse makes four trips down and back along the cable in 0.835 s. What is the tension in the cable? N

Explanation / Answer

1) f = 50.8 Hz

(a) A = 8.26/2 = 4.13 cm

(b) lamda = 2*5.2 = 10.4 cm

(c) T = 1/f = 1/50.8 = 0.0197 s

(d) v = f*lamda

v = 50.8*0.104

v = 5.28 m/s

2) v = 343 m/s, f = 4.89*10^4 Hz

v = f*lamda

343 = 4.84*10^4 *lamda

lamda = 0.0071 m

size of insect = 7.1 mm

3) L = 3.9 m , m = 0.195 kg

linear mass density u = m/L

u = 0.195/3.9 = 0.05 kg/m

distance travelled by puls d = 4*2*3.9

v = d/t

v = 4*2*3.9/0.835 = 37.365 m/s

v= (T/u)^0.5

37.365 = (T/0.05)^0.5

T = 69.8 N

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.