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3 years ago

HELLO , PLZ HELP .

Physics

1 answer:

sergey [27]3 years ago

6 0

Answer:

the pressure due to the water on the diver is 200,000 pascal

pressure = height × density × acceleration due to gravity

p = 20×1000×10

p=200,000 pascal

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How many seconds in a day? A hole day.

gizmo_the_mogwai [7]

1 year consists of 365 days. 1 day has 24 hours, each hour has 60 minutes and each minute has 60 seconds. 1 day = (24 hours/day) × (60 minutes/hour) × (60 seconds/minute) = 86400 seconds/day

Hope that helped :)

4 0

3 years ago

You pour 250 g of tea into a Styrofoam cup, initially at 80∘C and stir in a little sugar using a 100-g aluminum 20∘C spoon and l

jok3333 [9.3K]

To solve this problem it is necessary to apply the concepts related to the conservation of energy and heat transferred in a body.

By definition we know that the heat lost must be equal to the heat gained, ie

$Q_g = Q_l$

Where,

Q = Heat exchange

The heat exchange is defined as

$Q = c_p m \Delta T$

Where,

$c_p =$ Specific heat

m = mass

$\Delta T=$ Change in Temperature

Therefore replacing we have that

$Q_g = Q_l$

$c_{p-tea} m \Delta T = c_{p-al} m \Delta T$

Replacing with our values we have that

$0.25*4180*(80-T) = 0.1*900*(T-20)$

$11.61*(80-T) = T-20$

$T= \frac{948.8}{11.61}$

$T = 75.24\°C$

Therefore the highest possible temperature of the spoon when you finally take it out of the cup is 75.24°C

3 0

3 years ago

A spring stores potential energy U0 when it is compressed a distance x0 from its uncompressed length.

beks73 [17]

Answer:

Explanation:

Using Hooke's law

Elastic potential energy = 1/2 K x²

K is elastic constant of the spring

x is the extension of the spring

a) The elastic potential energy when the spring is compressed twice as much Uel = 1/2 k (2x₀) ² = 4 (1/2 kx₀²)= 4 U₀

b) when is compressed half as much Uel = 1/2 k $\frac{x0}{4} ^{2}$ = $\frac{1}{4}$ ( U₀)

c) make x₀ subject of the formula in the equation for elastic potential

x₀ = $\sqrt{\frac{2U0}{K} }$

x, the amount it will compressed to tore twice as much energy = $\sqrt{\frac{2 (2U0)}{K} }$

x = √2 x₀

d) x₁, the new length it must be compressed to store half as much energy = $\sqrt{\frac{2 (\frac{1}{2})U0 }{K} }$

x₁ = $\sqrt{\frac{1}{2} }$ x₀

5 0

3 years ago

Objects in motion eventually stop moving due to a _____ .can someone help me with this question

Tom [10]

External force.

Air resistance, friction, grass rubbing on a rolling ball, etc.

If there is no external force on a moving object, it keeps going.

Forever !

8 0

3 years ago

A strong lightning bolt transfers an electric charge of about 31 C to Earth (or vice versa). How many electrons are transferred?

olchik [2.2K]

Answer:

$m=5.78\times 10^{-3}\ g$

$n_e=1.935\times 10^{20}$ is the no. of electrons

Explanation:

Given:

quantity of charge transferred, $Q=31\ C$

No. of electrons in the given amount of charge:

As we have charge on one electron $1.602\times 10^{-19}\ C$

so,

$n_e=\frac{Q}{e}$

$n_e=\frac{31}{1.602\times 10^{-19}}$

$n_e=1.935\times 10^{20}$ is the no. of electrons

Now if each water molecules donates one electron:

Then we require $n=1.935\times 10^{20}$ molecules.

Now the no. of moles in this many molecules:

$n_m=\frac{n}{N_A}$

where

$N_A=6.022\times 10^{23}$ Avogadro No.

$n_m=\frac{1.935\times 10^{20}}{6.022\times 10^{23}}$

$n_m=3.213\times 10^{-4}\ moles$

We have molecular mass of water as M=18 g/mol.

So, the mass of water in the obtained moles:

$n_m=\frac{m}{M}$

where:

m = mass in gram

$3.213\times 10^{-4}=\frac{m}{18}$

$m=5.78\times 10^{-3}\ g$

7 0

3 years ago