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3 years ago

An object is dropped on Earth from a height of 15 m. How long did it take for the object to reach the ground?

Physics

1 answer:

Inga [223]3 years ago

6 0

x=gt^2/2=>t^2=2x/g=30/9.81=3.05=>t=sqrt(3.05)=1.8 s

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Find the deBroglie wavelength of an electron with 4.0 eV.

pantera1 [17]

Explanation:

It is given that,

Voltage, $V=4 eV=4\times 1.6\times 10^{-19}\ V= 6.4\times 10^{-19}\ V$

De broglie wavelength in terms of voltage is given by :

$\lambda=\dfrac{h}{\sqrt{2meV} }$

m and e are the mass and charge on electron. So,

$\lambda=\dfrac{12.27}{\sqrt{V} }\ A$

$\lambda=\dfrac{12.27}{\sqrt{6.4\times 10^{-19}} }\ A$

$\lambda=1.53\times 10^{10}\ A$

$\lambda=1.53\ m$

So, the De broglie wavelength of an electron is 1.53 meters. Hence, this is the required solution.

3 0

3 years ago

For a particle executing SHM with an amplitude ‘r’, the kinetic energy will be equal to the potential energy when the displaceme

pychu [463]

Answer:

x = A sin w t displacement in SHM

v = A w cos w t velocity in SHM

PE = 1/2 k x^2 = 1/2 k A^2 sin^2 w t

KE = 1/2 m v^2 = 1/2 m w^2 A^2 cos^2 w t

If KE = PE then

k sin^2 w t = m w^2 cos^2 w t

sin^2 wt / cos^2 w t = tan^2 w t = m w^2 / k

but k / m = w^2

So tan^2 w t = 1 and tan w t = 1 or w t = pi / 4 or theta = 45 deg

Then x = r sin w t = r sin 45 = .707 r

6 0

3 years ago

A ball is dropped off the side of a bridge. after 1.55 s, how far has it fallen

givi [52]

Answer:

38.64 feet

Explanation:

x=x0 + vx0t + 1/2axt2

x= 0 + 0 + 1/2 X 32.17 ft/sec2 X 1.55 sec2

x = 38.64 feet

7 0

4 years ago

Ozone gas in the atmosphere protects living things on Earth from some of the Sun's harmful

Marysya12 [62]

Answer:

Ozone is a compound.

Explanation:

Elements are simple atoms that can merge or combine to produce a bigger molecule called a compound. They can not be splitted into smaller atoms. Examples are: hydrogen, carbon, etc.

A compound is formed as a result of the combination of two or more elements. They can be splitted into elements. Examples are: ammonium, water, carbon dioxide etc.

Ozone ( $O_{3}$ ) is a less stable allotrope of oxygen which is made up of three atoms of oxygen. Therefore, it is a compound.

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3 years ago

How do objects move? What determines whether an object moves?

Mice21 [21]

When a force pushes or pulls the object, the object will move in the direction of the force. Force can make things move, change shape or change their speed. Some forces are direct and happen when two things touch (like a foot kicking a ball) or over a distance (such as a magnet or gravity)

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3 years ago