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3 years ago

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The specific heat of a liquid Y is 4.2 cal/g degrees Celsius. A sample grams of this liquid at 137 K is heated to 265K. The liqu

id absorbs. 7.82 kcal. What is the sample of liquid in grams?

1 answer:

sergiy2304 [10]3 years ago

8 0

Answer:

54

Explanation:

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A dinosaur and a mammoth elephant are walking away from each other in Jurassic Park When the mammoth is at a distance that is tw

Advocard [28]

Answer: gravitational force between them will be reduced by one - fourth ( 1/4) of its initial value.

Explanation: Gravitational force between two bodies obeys inverse square law. That is, gravitational force between two bodies is inversely proportional to the square of the distance between the two bodies.

When the mammoth is at a distance that is twice the original distance, the gravitational force between them will be reduced by one - fourth ( 1/4 ) of its initial value.

5 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, $Q=31\ C$

<u>No. of electrons in the given amount of charge:</u>

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.

<u>Now the no. of moles in this many molecules:</u>

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

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.

<u>So, the mass of water in the obtained moles:</u>

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

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

An experimental apparatus has two parallel horizontal metal rails separated by 1.0 m. A 3.0 Ω resistor is connected from the lef

Blizzard [7]

Answer:

The induced current and the power dissipated through the resistor are 0.5 mA and $7.5\times10^{-7}\ Watt$ .

Explanation:

Given that,

Distance = 1.0 m

Resistance = 3.0 Ω

Speed = 35 m/s

Angle = 53°

Magnetic field $B=5.0\times10^{-5}\ T$

(a). We need to calculate the induced emf

Using formula of emf

$E = Blv\sin\theta$

Where, B = magnetic field

l = length

v = velocity

Put the value into the formula

$E=5.0\times10^{-5}\times1.0\times35\sin53^{\circ}$

$E=1.398\times10^{-3}\ V$

We need to calculate the induced current

$E =IR$

$I=\dfrac{E}{R}$

Put the value into the formula

$I=\dfrac{1.398\times10^{-3}}{3.0}$

$I=0.5\ mA$

(b). We need to calculate the power dissipated through the resistor

Using formula of power

$P=I^2 R$

Put the value into the formula

$P=(0.5\times10^{-3})^2\times3.0$

$P=7.5\times10^{-7}\ Watt$

Hence, The induced current and the power dissipated through the resistor are 0.5 mA and $7.5\times10^{-7}\ Watt$ .

6 0

3 years ago

Read 2 more answers

A bicycle tire is spinning counterclockwise at 2.70 rad/s. During a time period Δt = 1.50 s, the tire is stopped and spun in the

Andru [333]

Answer:

Δω = -5.4 rad/s

αav = -3.6 rad/s²

Explanation:

<u>Given</u>:

Initial angular velocity = ωi = 2.70 rad/s

Final angular velocity = ωf = -2.70 rad/s (negative sign is

due to the movement in opposite direction)

Change in time period = Δt = 1.50 s

<u>Required</u>:

Change in angular velocity = Δω = ?

Average angular acceleration = αav = ?

<u>Solution</u>:

<u>Angular velocity (Δω):</u>

Δω = ωf - ωi

Δω = -2.70 - 2.70

Δω = -5.4 rad/s.

<u> Average angular acceleration (αav):</u>

αav = Δω/Δt

αav = -5.4/1.50

αav = -3.6 rad/s²

Since, the angular velocity is decreasing from 2.70 rad/s (in counter clockwise direction) to rest and then to -2.70 rad/s (in clockwise direction) so, the change in angular velocity is negative.

7 0

3 years ago

Read 2 more answers

The power of motor is 50 w the motor drags a 2 object horizontally at a constant speed of 10m/s along a rough floor . What is th

Ilia_Sergeevich [38]

Frictional force between the object and the floor=5 N

Explanation:

power= 50 W

velocity= 10 m/s

power= force * velocity

50=F * 10

F=50/10

F=5 N

Thus the force of friction= 5 N

5 0

3 years ago