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3 years ago

If you are sitting 8.20 m from a

Physics

1 answer:

Elanso [62]3 years ago

8 0

Answer:

Explanation:

There are a lot of assumptions needed for the calculation:

first is the speaker is a point source

second the speaker is 100% efficient in its output

third the sound output propagates as a sphere

Intensity = Power / Surface Area

= 70 / (4*pi*8.20^2)

= 0.082W/m^2

Converting into dB:

= 10*log ( Intensity / (1*10^-12))

= 10*log(0.0828/ (1*10^-12))

= 109 dB

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WhAT is the change IN THE entropy of 2.0kg of h2o molecules when transform at a constant pressure of 1 atm from water at 100 deg

Fynjy0 [20]

Answer:

The entropy change is 45.2 kJ/K.

Explanation:

mass of water at 100 C = 2 kg

Latent heat of vaporization, L = 2260 kJ/kg

Heat is

H = m L

H = 2 x 2260 = 4520 kJ

Entropy is given by

S = H/T = 4520/100 = 45.2 kJ/K

3 0

3 years ago

Why is it that the weight of an object weighing 1N air, weighs more when immersed in water ?

Anni [7]

There is no "why", because that's not what happens. The truth is
exactly the opposite.

Whatever the weight of a solid object is in air, that weight will appear
to be LESS when the object is immersed in water.

The object is lifted by a force equal to the weight of the fluid it displaces.
It displaces the same amount of air or water, and any amount of water
weighs more than the same amount of air. So the force that lifts the
object in water is greater than the force that lifts it in air, and the object
appears to weigh less in the water.

4 0

3 years ago

You have a summer job at a company that developed systems to safely lower large loads down ramps. Your team is investigating a m

Fofino [41]

Answer:

Note that the emf induced is

emf = B d v cos (A)

---> v = emf / [B d cos (A)]

where

B = magnetic field

d = distance of two rails

v = constant speed

A = angle of rails with respect to the horizontal

Also, note that

I = emf/R

where R = resistance of the bar

Thus,

I = B d v cos (A) / R

Thus, the bar experiences a magnetic force of

F(B) = B I d = B^2 d^2 v cos (A) / R, horizontally, up the incline.

Thus, the component of this parallel to the incline is

F(B //) = F(B) cos(A) = B I d = B^2 d^2 v cos^2 (A) / R

As this is equal to the component of the weight parallel to the incline,

B^2 d^2 v cos^2 (A) / R = m g sin (A)

where m = the mass of the bar.

Solving for v,

v = [R m g sin (A) / B^2 d^2 cos^2 (A)] [ANSWER, the constant speed, PART A]

******************************

v = [R m g sin (A) / B^2 d^2 cos^2 (A)]

Plugging in the units,

m/s = [ [ohm * kg * m/s^2] / [T^2 m^2] ]

Note that T = kg / (s * C), and ohm = J * s/C^2

Thus,

m/s = [ [J * s/C^2 * kg * m/s^2] / [(kg / (s * C))^2 m^2] ]

= [ [J * s/C^2 * kg * m/s^2] / [(kg^2 m^2) / (s^2 C^2)]

As J = kg*m^2/s^2, cancelling C^2,,

= [ [kg*m^2/s^2 * s * kg * m/s^2] / [(kg^2 m^2) / (s^2)]

Cancelling kg^2,

= [ [m^2/s^2 * s * m/s^2] / [(m^2) / (s^2)]

Cancelling m^2/s^2,

= [s * m/s^2]

Cancelling s,

=m/s [DONE! WE SHOWED THE UNITS ARE CORRECT! ]

8 0

3 years ago

A constant force is applied to an object, causing the object to accelerate at 10 m/s^2. What will the acceleration be if: a) The

Liula [17]

What you need to know is that the force is

F=ma

The force is the product of mass and acceleration

this means that the acceleration is

a=F/m

a) The force is halved?
this means that f will be $\frac{F}{2}$ now:

a= $\frac{F}{2m}$

So the accelaration will also he halved (it's the original acceleratation divided by 2)

b) The object's mass is halved?
a= $\frac{F}{m/2}$ =a= $\frac{F2}{m}$

which is the original acceleration times two!! so it will double

c) The force and the object's mass are both halved?
now we have

a= $\frac{F/2}{m/2}$ =a= $\frac{2F}{2m}$ =a= $\frac{F}{m}$

so they will cancel each other out and the acceleration will stay the same!

5 0

3 years ago

How is force useful as well as harmful.<br>Comment with the statement.

vladimir1956 [14]

No, we can't say force is useful or harmful. All else being equal, force is either not harmful or useful depending on the body that is applying it and where it is applying it.

Given how it affects motion, force is a crucial idea. It is a relationship that, in the absence of an opposing force, modifies an object's motion. However, a push or a pull that any object feels is the simplest definition of force. Due to the fact that force is a vector quantity, it possesses both a magnitude and a direction.

How force is useful

A body at rest can move with enough force.A body in motion may be slowed down or stopped by it.It has the power to quicken the pace of an object in motion.Along with its shape and size, it can also alter the direction of a moving body.

How force is harmful

Force has the power to alter an object's state of motion.
Moving objects can shift direction due to force.
Moving things' speeds can be increased by force.
Moving items can become slower due to force.
Force has the power to alter an object's shape.

Learn more about force here

brainly.com/question/14362949

#SPJ9

7 0

1 year ago