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3 years ago

A girl performed 50 J of work lifting a heavy box. It took her 5 seconds to lift the box. What was her power?

1 answer:

4 0

The formula for power is:
P = W / T (Power = Work / Time).

We have 50 Joules of work.
We have 5 seconds of time.

Let's plug in our numbers.
P = 50 / 5

Divide 50 / 5
50 / 5 = 10.

Your power is 10 Joules per second.

I hope this helps!

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A source containing a mixture of hydrogen and deuterium atoms emits light at two wavelengths whose mean is 540 nm and whose sepa

Ne4ueva [31]

Answer:

N=3176.5rulling

Explanation:

We were told that the source containing a mixture of hydrogen and deuterium atoms emits light with

wavelengths whose mean is 540 nm

Then λ= 540 nm, but we need to convert to metre which = (540× 10⁻⁹m)

Also whose separation is 0.170 nm, which mean the difference between the wavelength is 0.170 nm then

Δ λ = 0.170 nm the we convert to metre we have. Δλ= 0.170 nm= (0.170×10⁻⁹m)

the formular below can be used to can be used to calculate our minimum number of lines

N= λ /(m Δλ)

Where N is number of fillings i.e number of lines

λ= wavelength

Δλ= difference in wavelength

m=1

Then if we substitute the values we have

,N= (540× 10⁻⁹ m)/[(1)*(0.170× 10⁻⁹m)]

N =3176.5rulling

Therefore, minimum number of lines = =3176.5rulling

4 0

3 years ago

2. Consider a conical pendulum with a bob of mass m = 77.0 kg on a string of length L = 10.0 m that makes an angle of ???? 3.00°

bekas [8.4K]

Explanation:

It is given that,

The mass of bob, m = 77 kg

Length of the string, L = 10 m

Angle made by the string with the vertical, $\theta=3^{\circ}$

(a) Let T is the force exerted by the string on the pendulum. At equilibrium,

$T\ cos\theta=mg$

$T=\dfrac{mg}{cos\theta}$

$T=\dfrac{77\times 9.8}{cos(3)}$

T = 755.63 N

The horizontal component of the force is given by,

$T_H=T\ sin\theta$

$T_H=755.63\ sin(3)=39.54\ N$

The vertical component of the force is given by,

$T_V=T\ sin\theta=mg$

$T_V=754.59\ N$

(b) Let a is the radial acceleration of the bob. It can be calculated as :

$a=\dfrac{T_H}{m}$

$a=\dfrac{39.54\ N}{77\ kg}$

$a=0.51\ m/s^2$

Hence, this is the required solution.

6 0

3 years ago

If a 4kg Bird is pushed by the window with a force of 60 N how fast is the bird accelerate?

LiRa [457]

Force=60N
Mass=4kg

$\\ \ast\sf\hookrightarrow Force=Mass\times Acceleration$

$\\ \ast\sf\hookrightarrow Acceleration=\dfrac{Force}{Mass}$

$\\ \ast\sf\hookrightarrow Acceleration=\dfrac{60}{4}$

$\\ \ast\sf\hookrightarrow Acceleration=15m/s^2$

3 0

3 years ago

In 8,450 seconds, the number of radioactive nuclei decreases to 1/16 of the number present initially. What is the half-life (in

almond37 [142]

Answer:

<h2>2113 seconds</h2>

Explanation:

The general decay equation is given as $N = N_0e^{-\lambda t} \\\\$ , then;

$\dfrac{N}{N_0} = e^{-\lambda t} \\$ where;

$N/N_0$ is the fraction of the radioactive substance present = 1/16

$\lambda$ is the decay constant

t is the time taken for decay to occur = 8,450s

Before we can find the half life of the material, we need to get the decay constant first.

Substituting the given values into the formula above, we will have;

$\frac{1}{16} = e^{-\lambda(8450)} \\\\Taking\ ln\ of \both \ sides\\\\ln(\frac{1}{16} ) = ln(e^{-\lambda(8450)}) \\\\\\ln (\frac{1}{16} ) = -8450 \lambda\\\\\lambda = \frac{-2.7726}{-8450}\\ \\\lambda = 0.000328$