In which century was the DNA database established?

A fire engine approaches a wall at 5 m/s while the siren emits a tone of 500 Hz frequency. At the time, the speed of sound in ai

Svetach [21]

Answer:

The values is $f_b =14.9 \ beats/s$

Explanation:

From the question we are told that

The speed of the fire engine is $v = 5\ m/s$

The frequency of the tone is $f = 500 \ Hz$

The speed of sound in air is $v_s = 340 \ m/s$

The beat frequency is mathematically represented as

$f_b = f_a - f$

Where $f_a$ is the frequency of sound heard by the people in the fire engine and is is mathematically evaluated as

$f_a = [\frac{v_s + v }{v_s -v} ]* f$

substituting values

$f_a = [\frac{340 + 5 }{340 -5} ]* 500$

$f_a = 514.9 \ Hz$

Thus

$f_b =514.9 - 500$

$f_b =14.9 \ beats/s$

8 0

2 years ago

Density: Two blocks, A and B, are put in a tank of water. Block A has a density of 1.21 g/cm³. Block B has a density of 1.37 g/c

stira [4]

Answer:

Block A

Explanation:

Block A will float higher in the water compared to the second Block.

The density of water is 1g/cm³.

According to the principle of floatation "an object that floats in a liquid will displace equal amount of fluid to the weight of the object".

A body will become more submerged in water if it has more density because density is the mass per volume of body.

An object with a higher density than another will sink in the liquid of the one with lesser density.

Object A has lesser density and will float higher up and displace very little water.
Object B has higher density and will be more submerged.

4 0

2 years ago

Two piano strings produce beats. Frequencies of the strings are 1560 Hz. and 1563 Hz. Choose the correct frequency of the beats.

kakasveta [241]

Beat frequency is given by the difference of two frequencies played together

$f_{beat} = |f_1 - f_2|$

given that

$f_1 = 1560 Hz$

$f_2 = 1563 Hz$

Now

$f_{beat} = |1560- 1563| Hz$

$f_{beat} = 3 Hz$

3 0

3 years ago

Read 2 more answers

Assuming typical speeds of 8.5 km/s and 5.5 km/s for P and S waves, respectively, how far away did the earthquake occur if a par

taurus [48]

Answer:

The earthquake occurred at a distance of 1122 km

Explanation:

Given;

speed of the P wave, v₁ = 8.5 km/s

speed of the S wave, v₂ = 5.5 km/s

The distance traveled by both waves is the same and it is given as;

Δx = v₁t₁ = v₂t₂

let the time taken by the wave with greater speed = t₁

then, the time taken by the wave with smaller speed, t₂ = t₁ + 1.2 min, since it is slower.

v₁t₁ = v₂t₂

v₁t₁ = v₂(t₁ + 1.2 min)

v₁t₁ = v₂(t₁ + 72 s)

v₁t₁ = v₂t₁ + 72v₂

v₁t₁ - v₂t₁ = 72v₂

t₁(v₁ - v₂) = 72v₂

$t_1 = \frac{72v_2}{v_1-v_2}\\\\t_1 = \frac{72*5.5}{8.5-5.5}\\\\t_1 = 132 \ s$

The distance traveled is given by;

Δx = v₁t₁

Δx = (8.5)(132)

Δx = 1122 km

Therefore, the earthquake occurred at a distance of 1122 km

4 0

2 years ago

Joe is trying to soup up his dragster. He knows that the time needed for the car to go from 0 to 100 miles per hour varies inver

Tatiana [17]

Translating the first sentence into equation we get, t = k(1/h) where t is time in seconds, k is the constant and h is the horsepower. Substituting the values in the equation we have, 12s = k(1/200) we have a k = 2400 seconds – hp. To get the time at 240 hp we use the equation above and the constant, we get, t = (2400 seconds-hp)(1/240hp) t = 10seconds.

6 0

3 years ago