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3 years ago

Which has frequency below the audible range? (a) Ultrasonic (b) Supersonic (c) Infrasonic (d) All of these

Physics

1 answer:

EastWind [94]3 years ago

8 0

Answer:

option (c)

Explanation:

The frequency ranges for infrasonic is below 20 Hz.

The frequency ranges for audible is 20 Hz to 20000 Hz.

The frequency ranges for ultrasonic is above 20000 Hz.

So, infrasonic have frequency below the audible range. We cannot hear this frequency.

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Directions: Select ALL the correct answers.

nordsb [41]

Definitely D. The brakes on a bike rub against the wheel. Not sure about the others.

5 0

3 years ago

The magnitude of Earth’s magnetic field is about 0.5 gauss near Earth’s surface. What’s the maximum possible magnetic force on a

vampirchik [111]

Answer:

$F = 1.5 \times 10^{-16} N$

this force is $1.68 \times 10^{13}$ times more than the gravitational force

Explanation:

Kinetic Energy of the electron is given as

$KE = 1 keV$

$KE = 1 \times 10^3 (1.6 \times 10^{-19}) J$

$KE = 1.6 \times 10^{-16} J$

now the speed of electron is given as

$KE = \frac{1}{2}mv^2$

now we have

$v = \sqrt{\frac{2 KE}{m}}$

$v = 1.87 \times 10^7 m/s$

now the maximum force due to magnetic field is given as

$F = qvB$

$F = (1.6\times 10^{-19})(1.87 \times 10^7)(0.5 \times 10^{-4})$

$F = 1.5 \times 10^{-16} N$

Now if this force is compared by the gravitational force on the electron then it is

$\frac{F}{F_g} = \frac{1.5 \times 10^{-16}}{9.1 \times 10^{-31} (9.8)}$

$\frac{F}{F_g} = 1.68 \times 10^{13}$

so this force is $1.68 \times 10^{13}$ times more than the gravitational force

4 0

3 years ago

Help please :pensive:

tino4ka555 [31]

Answer:

0m/s²

Explanation:

Given parameters:

Initial velocity of the boat = 8m/s

Final velocity = 8m/s

Time taken = 4s

Unknown:

Acceleration of the boat = ?

Solution:

Acceleration is the rate of change of velocity with time.

It is mathematically expressed as;

A = $\frac{v - u}{t}$

A is the acceleration

v is the final velocity

u is the initial velocity

t is the time taken

Insert the parameters and solve;

A = $\frac{8-8}{4}$ = 0m/s²

6 0

3 years ago

Two bicyclist, originally separated by a distance of 20 miles, are each traveling at a uniform speed of 10 miles per hour toward

Radda [10]

Answer:

D = 25 miles

Explanation:

To solve this problem, we just need to know how much time it took both bicyclists to collide and that will be the same amount of time that the bee flew at 25miles per hour. With those values we could calculate the distance it traveled.

Since both bicyclists collide, we know that Xa=Xb, so:

Xa = V*t = 10*t and Xb = 20 - V*t = 20 - 10*t

10*t = 20 - 10*t Solving for t:

t = 1 hour Now we can calculate the distance for the bee:

D = Vbee * t = 25 * 1 = 25 miles

6 0

3 years ago

A dart with mass md is launched toward a block of mass mb that is suspended from a string of length L. The dart is moving horizo

Yuki888 [10]

Answer:

A) Impulse is the same for both the objects

B) The higher is the speed, the greater will be the height.

Explanation:

Part a)

The time of interaction of the two bodies i.e the hanging mass and the stick is same. Thus, force caused by dart on the block = force caused by block on the dart. Hence, impulse is the same for both the objects.

Part B

The energy will be conserved in the entire reaction process

Hence, Kinetic energy = potential energy

0.5Mv^2 = gh(md+mb)

H is directly proportional to the square of speed.

Hence, the higher is the speed, the greater will be the height.

5 0

3 years ago