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3 years ago

10

Which wave would have the greatest wave speed , a wave from a vibrating piano string in an auditorium or a sound wave created by

a boat anchor striking an underwater rock

2 answers:

fenix001 [56]3 years ago

7 0

The one in the water would have a much greater speed than the one in the air since energy is transmitted better and faster in liquid than gas.

ki77a [65]3 years ago

6 0

Answer:

a wave from a vibrating piano string in an auditorium

Explanation:

As we know that the speed of wave depends on two factors

1) Elasticity of medium

2) density of the medium

So here we know that

greatest speed out of the two given medium is for vibrating string of piano

as we know that

$v = \sqrt{\frac{T}{\mu}}$

so we have

more speed in stretched string

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Wil-E-Coyote drops a bowling ball off a cliff to try to catch the Roadrunner. The cliff is

PtichkaEL [24]

Answer:

t = 5.19 s

Explanation:

We have,

Height of the cliff is 132 m

It is required to find the time taken by the ball to fall to the ground. Let t is the time taken. So, using equation of kinematics as :

$y=ut+\dfrac{1}{2}gt^2\\\\\text{since}\ u=0\\\\y=\dfrac{1}{2}gt^2\\\\t=\sqrt{\dfrac{2y}{g}}\\\\t=\sqrt{\dfrac{2\times 132}{9.8}}\\\\t=5.19\ s$

So, it will take 5.19 seconds to fall to the ground.

8 0

3 years ago

Compare how magnetic forces act through non-magnetic materials and<br>magnetic materials:

gavmur [86]

<h2>Compare how magnetic forces act through non-magnetic materials and </h2><h2>magnetic materials:</h2>

Explanation:

Magnet

• Magnet :- is an object which attracts pieces of iron, steel etc towards itself.

Some facts about magnets:-

• When magnet is freely suspended it always align towards north-south direction

• Like poles always repel & opp. poles attract each other.

• Magnet always exist as dipole

• Two poles can never be separated : if we try to cut it then still both the poles will exist even ina small piece of magnet .it automatically develops the lost polarity

Magnet always develop certain area around it where its effect can be felt ie. magnetic field.

MAGNETIC Field

is studied by drawing imaginary lines called magnetic lines of forces.

Characteristics.

• They always originate from North pole & terminate at South pole. This shows that if north pole was free is move it would have mvre towards south pole.

•Place where they are closer indicate strong M. field i.e. at poles.

•Mag. Field lines gives the direction of magnetic force.

•Two magnetic lines will never intersect each other as they give direction of force & force can’t have 2 direction at a time.

M Field lines are closed continuous curves.

This is what that happens in magnetic materials .

Non magnetic materials

Magnetic forces 'act through' non-magnetic materials
These magnetic materials can be used as a shield around a magnet.
The domain theory of magnetism tries to explain why metals get magnetised
. The magnetic elements have little molecular magnets inside them.
Magnets attract only the magnetic materials

Types of magnetic materials

Soft magnetic materials (e.g. iron) have domains that easily move into line when the metal is placed in a magnetic field but as soon as the field is removed the domains take on a random pattern again. It returns to being unmagnetized straight away.

Hard magnetic materials (e.g. steel) have domains that do not easily move into line when the metal is placed in a magnetic field, a strong field is needed for some time, but then, when the field is removed the domains retain the magnetic pattern. The metal stays magnetic for a long time.

5 0

3 years ago

suppose you press a basketball against a wall. what happpens to the basketball when you are pressing it?

AURORKA [14]

It hardens because you are pressing it against something.

5 0

3 years ago

A cannon fires a 0.2 kg shell with initial velocity vi = 9.2 m/s in the direction θ = 46 ◦ above the horizontal. The shell’s tra

Sedbober [7]

Answer:

∆h = 0.071 m

Explanation:

I rename angle (θ) = angle(α)

First we are going to write two important equations to solve this problem :

Vy(t) and y(t)

We start by decomposing the speed in the direction ''y''

$sin(\alpha) = \frac{Vyi}{Vi}$

$Vyi = Vi.sin(\alpha ) = 9.2 \frac{m}{s} .sin(46) = 6.62 \frac{m}{s}$

Vy in this problem will follow this equation =

$Vy(t) = Vyi -g.t$

where g is the gravity acceleration

$Vy(t) = Vyi - g.t= 6.62 \frac{m}{s} - (9.8\frac{m}{s^{2} }) .t$

This is equation (1)

For Y(t) :

$Y(t)=Yi+Vyi.t-\frac{g.t^{2} }{2}$

We suppose yi = 0

$Y(t) = Yi +Vyi.t-\frac{g.t^{2} }{2} = 6.62 \frac{m}{s} .t- 4.9\frac{m}{s^{2} } .t^{2}$

This is equation (2)

We need the time in which Vy = 0 m/s so we use (1)

$Vy (t) = 0\\0=6.62 \frac{m}{s} - 9.8 \frac{m}{s^{2} } .t\\t= 0.675 s$

So in t = 0.675 s → Vy = 0. Now we calculate the y in which this happen using (2)

$Y(0.675s) = 6.62\frac{m}{s}.(0.675s)-4.9 \frac{m}{s^{2} } .(0.675s)^{2} \\Y(0.675s) =2.236 m$

2.236 m is the maximum height from the shell (in which Vy=0 m/s)

Let's calculate now the height for t = 0.555 s

$Y(0.555s)= 6.62 \frac{m}{s} .(0.555s)-4.9\frac{m}{s^{2} } .(0.555s)^{2} \\Y(0.555s) = 2.165m$

The height asked is

∆h = 2.236 m - 2.165 m = 0.071 m

6 0

3 years ago

A meter stick A hurtles through space at a speed v = 0.25c relative to you, with its length aligned with the direction of motion

yaroslaw [1]

Answer:

$L_0\approx1.0328\ m$

Explanation:

Given:

relativistic length of stick A, $L=1\ m$

relativistic velocity of stick A with respect to observer, $v=0.25c=7.5\times 10^{7}\ m.s^{-1}$

<em>Since the object is moving with a velocity comparable to the velocity of light with respect to the observer therefore the length will appear shorter according to the theory of relativity.</em>

<u> Mathematical expression of the theory of relativity for length contraction:</u>

$L=\frac{L_0}{\gamma}$

where:

L = relativistic length

$L_0=$ original length at rest

$\gamma =$ Lorentz factor $=\frac{1}{\sqrt{1-\frac{v^2}{c^2} } }$

$\Rightarrow 1=\frac{L_0}{\frac{1}{\sqrt{1-\frac{(0.25c)^2}{c^2} } }}$

$L_0=\frac{1}{\sqrt{1-\frac{(0.25c)^2}{c^2} } }$

$L_0\approx1.0328\ m$

4 0

3 years ago