PHYSICS HIGH SCHOOL

A heart defibrillator is used to enable the heart to start beating if it has stopped. This is done by passing a large current of 12 A through the body at 25 V for a very short time, usually about 3.0 ms. (a) What power does the defibrillator deliver to the body, and (b) how much energy is transferred

Answers

Answer 1

Answer:

Answer:

(a) 300 W

(b)0.90 J

Explanation:

(a) The electric power for any circuit element is given as

$P=IV$

Here I is current passing in the circuit and V is the voltage.

Given I = 12 A and V =25 V.

Substitute the given values, we get

$P=12 A *25 V$

P = 300 W.

Thus, the power defibrillator deliver to the body is 300 W.

(b) To calculate the electric energy use the relation between electric energy, power and time as

$E=Pt$

Given t = 3 ms.

Substitute the values, we get

$E=300 W* 3* 10^-^3s$

E = 0.90 J.

Thus, the energy transferred is 0.90 J.

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For Most Substances the distance between particles is smallest when the substancea.exists gas
b.exists as a liquid
c.exists as a crystalline solid
d.exists as an amorphous solid

Answers

I am pretty sure that for Most Substances the distance between particles is smallest when the substance c.exists as a crystalline solid. I pick this option because crystalline solid is the most compact substances unlike the others.
It will definitely help you.

Answer:

c.exists as a crystalline solid

Explanation:

Amongst all the three phases, it is solid phase which is the most compact because the atoms within the solids are bound with a very strong force of attraction. But, solids can exist as either crystalline solid or amorphous solid. Between these two type of solids, it is crystalline solids which are very well packed and the inter atomic distance between their two atoms is the least. It is due to the reason that the atoms within a crystalline solid are arranged in proper order in the form of stacks. But, in amorphous solids the atoms are not arranged properly i.e. their arrangement is random which leads to the increased inter atomic distance. Second comes liquid phase, in liquids the inter atomic forces are intermediate between solids and gases. Atoms in a gas are bound with the weakest force of attraction known as van der Waals that is why the distance between the atoms of a gas is the highest.

1. A player kicks a football from ground level with an initial velocity of 22m/s, 35° above the horizontal. Assume that air resistance is negligible. Find the ball’s hang time.a. Find the maximum height of the ball in question 2.

b. Find the ball’s range from question 2.

Answers

Answer:

2.57 s

8.12 m

46.4 m

Explanation:

1. In the y direction:

s = 0 m

u = 22 sin 35° m/s = 12.6 m/s

a = -9.8 m/s²

Find: t

s = ut + ½ at²

0 = (12.6) t + ½ (-9.8) t²

t = 2.57 s

2. In the y direction:

u = 12.6 m/s

v = 0 m/s

a = -9.8 m/s²

Find: s

v² = u² + 2as

0² = (12.6)² + 2 (-9.8) s

s = 8.12 m

3. In the x direction:

u = 22 cos 35° m/s = 18.0 m/s

a = 0 m/s²

t = 2.57 s

Find: s

s = ut + ½ at²

s = (18.0) (2.57) + ½ (0) (2.57)²

s = 46.4 m

In the mobile m1=0.42 kg and m2=0.47 kg. What must the unknown distance to the nearest tenth of a cm be if the masses are to be balanced? The answer is 13.4 In the mobile what is the value for m3 to the nearest hundredth of a kilogram?

Answers

Complete Question

The complete question is shown on the first uploaded image

Answer:

Explanation:

From he question we are told that

The first mass is $m_1 = 0.42kg$

The second mass is $m_2 = 0.47kg$

From the question we can see that at equilibrium the moment about the point where the string holding the bar (where $m_1 \ and \ m_2$ are hanged ) is attached is zero

Therefore we can say that

$m_1 * 15cm = m_2 * xcm$

Making x the subject of the formula

$x = (m_1 * 15)/(m_2)$

$= (0.42 * 15)/(0.47)$

$x = 13.4 cm$

Looking at the diagram we can see that the tension T on the string holding the bar where $m_1 \ and \ m_2$ are hanged is as a result of the masses ( $m_1 + m_2$ )

Also at equilibrium the moment about the point where the string holding the bar (where ( $m_1 +m_2$ ) and $m_3$ are hanged ) is attached is zero

So basically

$(m_1 + m_2 ) * 20 = m_3 * 30$

$(0.42 + 0.47) * 20 = 30 * m_3$

Making $m_3$ subject

$m_3 = ((0.42 + 0.47) * 20 )/(30 )$

$m_3 = 0.59 kg$

At what water temperature will additional heat energy need to be added before the temperature will change again?A. –10°C
End of exam
B. 0°C
C. 10°C
D. 110°C

Answers

That would be 0 degrees Celsius aka the melting point of water.... If you look at the diagram I attached you notice that at 0 degrees Celsius it is flat, this is because much heat is needed at this point for water to rise to 1 degree... It is the same for the boiling point (100)

an egg is thrown straight up at the edge of a 100m cliff with an initial velocity of 20m/s. how long will it take for the egg to hit the ground below?

Answers

5 seconds

100 / 20 = 5

Iron filings sprinkled near a magnet arrange themselves into a pattern that illustrates the _____.magnetic poles
magnetic field
magnetic domain
magnetic alignment

Answers

Iron filings sprinkled near a magnet arrange themselves into pattern that illustrate the Magnetic fields. Magnetic fields are both about illustrate electric currents and magnetic materials. That's the reason why the iron filings arranges themselves into pattern when sprinkled near a magnet.

magnetic filed hope it helps

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