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3 years ago

1. A rock is dropped off a cliff and strikes the ground with an impact velocity of 35 m/s. How

Physics

1 answer:

MissTica3 years ago

4 0

Answer:

45 m

Explanation:

Use Big Five #5 with v0 = 0 (calling down the positive direction).

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What is the value for the kinetic energy for a n = 5 Bohr orbit electron in zeptoJoules?

Ne4ueva [31]

Answer:

The kinetic energy is 86.6 zepto joules.

Explanation:

Given that,

Number of orbit n =5

We know that,

Bohr's radius for hydrogen atom is

$r = 0.53\times10^{-10}\times n^2\ m$

Now, put the value of n in the formula of radius

$r=0.53\times10^{-10}\times5^2$

$r =1.33\times10^{-9}\ m$

We need to calculate the kinetic energy

Using formula of kinetic energy

$E_{k}=\dfrac{1}{4\pi\epsilon_{0}}\times\dfrac{e^2}{2\times r_{s}}$

Put the value into the formula

$E_{k}=\dfrac{9\times10^{9}\times(1.6\times10^{-19})^2}{2\times1.33\times10^{-9}}$

$E_{k}=8.66\times10^{-20}\ J$

We know that,

$1\ zepto\ joule=1\times10^{-21}\ J$

The kinetic energy is

$E_{k}=\dfrac{8.66\times10^{-20}}{1\times10^{-21}}$

$E_{k}=86.6\ zepto\ Joules$

Hence, The kinetic energy is 86.6 zepto joules.

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3 years ago

I need help for a review sheet

siniylev [52]

Tin is Sn, atomic number 47 is Silver, Mass of sodium is 22.9 u

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3 years ago

Correct Number Formats Numbers may be entered in several formats - including scientific notation and numerical expressions.

Illusion [34]

Answer:

a. Valid

b. Invalid

c. Invalid

d. Invalid

e. Valid

f. Valid

g. Invalid

Explanation:

Since, it follows all the four rules,

Therefore, this number is Valid

It uses upper case E, instead of lower case e.

Therefore, it is Invalid

It violates third rule for including unit.

Therefore, it is Invalid

It violates the first rule. As, there is a space between 6 and e. While in the example given in question, there is no gap.

Therefore, it is Invalid

Since, it follows all the four rules,

Therefore, this number is Valid

Since, it follows all the four rules,

Therefore, this number is Valid

It violates third rule for including unit.

Therefore, it is Invalid

6 0

3 years ago

A smooth circular hoop with a radius of 0.800 m is placed flat on the floor. A 0.300-kg particle slides around the inside edge o

Marrrta [24]

Answer:

a)11.25 J

b)Number of revolution = 1

Explanation:

Given that

Radius ,r= 0.8 m

m= 0.3 kg

Initial speed ,u= 10 m/s

final speed ,v= 5 m/s

Initial energy

$KE_i=\dfrac{1}{2}mu^2$

$KE_i=\dfrac{1}{2}0.3\times 10^2$

KEi= 15 J

Final kinetic energy

$KE_f=\dfrac{1}{2}mv^2$

$KE_f=\dfrac{1}{2}0.3\times 5^2$

KEf=3.75 J

The energy transformed from mechanical to internal = 15 - 3.75 J = 11.25 J

The minimum value to complete the circular arc

$V=\sqrt{r.g}$

Now by putting the values

$V=\sqrt{0.8\times 10}$

V= 2.82 m/s

So kinetic energy KE

$KE=\dfrac{1}{2}mV^2$

$KE=\dfrac{1}{2}0.3\times 2.82^2$

KE=1.19 J

ΔKE= KEi - KE

ΔKE= 15- 1.19 J

ΔKE=13.80 J

The minimum energy required to complete 2 revolutions = 2 x 11.25 J

= 22.5 J

Here 22.5 J is greater than 13.8 J.So the particle will complete only one revolution.

Number of revolution = 1

4 0

3 years ago

What is the Ozone layer?

yaroslaw [1]

"a layer in the earth's stratosphere at an altitude of about 6.2 miles (10 km) containing a high concentration of ozone, which absorbs most of the ultraviolet radiation reaching the earth from the sun."

Hope this helps!

4 0

3 years ago

Read 2 more answers