Question

A source of sound produces wave in air of wave length, 3.42m if the speed of sound in air is 330m/s. What is the period of vibration.

Answer 1

Answer:

1: INTRODUCTION: THE NATURE

OF SCIENCE AND PHYSICS

1.2 PHYSICAL QUANTITIES AND UNITS

4. American football is played on a 100-yd-long field, excluding the end zones. How long

is the field in meters? (Assume that 1 meter equals 3.281 feet.)

Solution Since 3 feet = 1 yard and 3.281 feet = 1 meter, multiply 100 yards by these conversion

factors to cancel the units of yards, leaving the units of meters:

91.4 m

3.281ft

1m

1 yd

3ft 100 yd =100 yd× × =

A football field is 91.4 m long.

10. (a) Refer to Table 1.3 to determine the average distance between the Earth and the

Sun. Then calculate the average speed of the Earth in its orbit in kilometers per

second. (b) What is this in meters per second?

Solution (a) The average speed of the earth’s orbit around the sun is calculated by dividing the

distance traveled by the time it takes to go one revolution:

20 km/s

3600 s

1h

24 h

1d

365.25 d

2 (10 km)

1 year

2 (average dist of Earth to sun) average speed

8

= × × =

=

π

π

The earth travels at an average speed of 20 km/s around the sun.

(b) To convert the average speed into units of m/s, use the conversion factor: 1000 m

Answer 2

Answer:

If the wavelength of a sound wave is 3.42m and the speed of sound in air is 330m/s, then the period of vibration is $10ms$

Explanation:

• The frequency (f) of the sound wave is the number of vibrations per second

• The time period (T) is $T=1/f$

• For a wave moving with a speed (V), the wavelength (λ) is the distance between compressions or rarefactions in a sound wave

        λ$=V/f$

From the question, we have

the wavelength of the given wave λ$=3.42m$

the speed of the wave $V=330m/s$

⇒the time period $T$=λ/$V$$=3.42/330=10ms$