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2 years ago

How many calories are equal to one BTU? (One calorie = 4.186 J, one BTU = 1 054 J.)

Physics

2 answers:

natima [27]2 years ago

5 0

Answer:

Explanation:

Given

1 calorie is equals to 4.186 J

and 1 BTU equals to 1054 J

using unitary method

$1\ calorie \equiv 4.186 J$

$1\ calorie \equiv 4.186 \times 1 J$

and $1\ J \equiv \frac{1}{1054} BTU$

thus $1\ calorie \equiv 4.186 \times \frac{1}{1054} BTU$

$1\ calorie\ \equiv 0.00397 BTU$

$1\ calorie\ \equiv 397\time 10^{-5} BTU$

or $BTU=251.88\approx 252 cal$

expeople1 [14]2 years ago

4 0

Answer:

option (c)

Explanation:

According to the question

1 BTU = 1054 J

4.186 J = 1 cal

So, 1 J = 1/4.186 cal

So, 1054 J = 1054 / 4.186 cal

= 251.8 cal

By rounding off, it is 252 cal

So, 1 BTU = 252 cal

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A red laser with a wavelength of 670 nm and a blue laser with a wavelength of 450 nm emit laser beams with the same light power.

tatyana61 [14]

E=hf C=wavelength*F

E=hC/wavelength

E=(6.626*10^-34)*(3.00*10^8)/670*10^-9

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3 years ago

A train slows from 60m/s to 20m/s in 50s

Dovator [93]

Answer:

a = -4/5 m/s^2

Explanation:

Acceleration = change in velocity / time

change in velocity = final velocity - initial velocity

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1 year ago

Read 2 more answers

A huge tank of glycerine with a density of 1.260 g/cm3 is vertically stationed on a platform which is 15 m above the ground. The

EleoNora [17]

Answer:

The tank is losing $4.976*10^{-4} m^3/s$

$v_g = 19.81 \ m/s$

Explanation:

According to the Bernoulli’s equation:

$P_1 + 1 \frac{1}{2} \rho v_1^2 + \rho gh_1 = P_2 + \frac{1}{2} \rho v_2^2 + \rho gh_2$

We are being informed that both the tank and the hole is being exposed to air :

∴ P₁ = P₂

Also as the tank is voluminous ; we take the initial volume $v_1$ ≅ 0 ;

then $v_2$ can be determined as: $\sqrt{[2g (h_1- h_2)]$

h₁ = 5 + 15 = 20 m;

h₂ = 15 m

$v_2 = \sqrt{[2*9.81*(20 - 15)]$

$v_2 = \sqrt{[2*9.81*(5)]$

$v_2= 9.9 \ m/s$ as it leaves the hole at the base.

radius r = d/2 = 4/2 = 2.0 mm

(a) From the law of continuity; its equation can be expressed as:

J = $A_1v_2$

J = πr² $v_2$

J = $\pi *(2*10^{-3})^{2}*9.9$

J = $1.244*10^{-4} m^3/s$

How fast is the water from the hole moving just as it reaches the ground?

In order to determine that; we use the relation of the velocity from the equation of motion which says:

v² = u² + 2gh ₂

v² = 9.9² + 2×9.81×15

v² = 392.31

The velocity of how fast the water from the hole is moving just as it reaches the ground is : $v_g = \sqrt{392.31}$

$v_g = 19.81 \ m/s$

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2 years ago

80N force ;

lutik1710 [3]

The power of the engine is 320 W.

<u>Explanation:</u>

Power may be defined as the rate of doing work (or) work done per unit time. One unit of energy is used to do the one unit of work.

Power = Work done / Time taken

Given, Force = 80 N, height = 5 m , final velocity = 4 m/s

To calculate the power, we must know the time taken.

To find the time, use the distance and speed formula which is given by

Time = Distance / speed

Here distance = 5 m and speed = 4 m/s

Time = 5 / 4 = 1.25 s.

Now, Power = work done / time

= (F * d) / t = (80 * 5) / 1.25

Power = 320 W.

The standard unit of power is watt (W) which is joule per second.

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3 years ago

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Juli2301 [7.4K]

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Since the body is in constant free fall, that is, a point where gravity tends to be zero:

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