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3 years ago

9. A student walks 2 km in 30 minutes. What

Physics

1 answer:

Alina [70]3 years ago

8 0

Answer:

4km/hr

Explanation:

There are 60 minute in an hour. If you divided 60 by 30 minutes you’d get 2. 2x 2km is 4km and 30x 2 is 60/an hour

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Which of the following is the proper unit for measuring power? Newton Joules Watts Meters

fredd [130]

The unit for power is Watts. the newton is a unit for force. joules for energy and meters for distance

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3 years ago

The resolving power of electron microscopes is much better than the resolving power of light microscopes because the wavelength

Misha Larkins [42]

Answer:

because the wavelength of electron beams is much shorter than the wavelength of visible light

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3 years ago

Alpha particles, each having a charge of +2e and a mass of 6.64 ×10-27 kg, are accelerated in a uniform 0.50 T magnetic field to

sergij07 [2.7K]

Answer:

$KE=1.2036\times 10^{-12}\ J$

Explanation:

Given:

charge on the alpha particle, $q=2e=3.2\times 10^{-19}\ C$

mass of the alpha particle, $m=6.64\times 10^{-27}\ kg$

strength of a uniform magnetic field, $B=0.5\ T$

radius of the final orbit, $r=0.5\ m$

<u>During the motion of a charge the magnetic force and the centripetal forces are balanced:</u>

$q.v.B=m.\frac{v^2}{r}$

$m.v=q.B.r$

where:

v = velocity of the alpha particle

$v=\frac{q.B.r}{m}$

$v=\frac{3.2\times 10^{-19}\times 0.5\times 0.5}{6.64\times 10^{-27}}$

$v=1.2048\times 10^{7}\ m.s^{-1}$

Here we observe that the velocity of the aprticle is close to the velocity of light. So the kinetic energy will be relativistic.

<u>We firstly find the relativistic mass as:</u>

$m'=\frac{1}{\sqrt{1-\frac{v^2}{c^2} } } \times m$

$m'=\frac{6.64\times 10^{-27}}{\sqrt{1-\frac{(1.2048\times 10^7)^2}{(3\times 10^8)^2} } }$

$m'=6.6533\times10^{-27}\ kg$

now kinetic energy:

$KE=m'.c-m.c$

$KE=6.6533\times 10^{-27}\times (3\times 10^8)^2-6.64\times 10^{-27}\times (3\times 10^8)^2$

$KE=1.2036\times 10^{-12}\ J$

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3 years ago

Swinging a tennis racket against a ball is an example of a third class lever. Please select the best answer from the choices pro

kari74 [83]

that statement is true

a Third class lever applied when the effort place between the load and the fulcrum.

For example, in a forearm serve
Fulcrum : The elbow
Effort : The effort that putted by the biceps muscle
Load : The arm

7 0

3 years ago

Read 2 more answers

Which formula can be used to solve problems related to the first law of thermodynamics? q = w u q = u – deltaw q = u w q = u – w

Orlov [11]

"Q = ΔU + W" is the equation is used to solve the questions related to "First law of thermodynamics".

<h3> What is the first law of thermodyanamics?</h3>

"First law of thermodynamics" states that "energy" neither created nor destroyed, but it can transfer from "one form of energy" to "another form of energy".

This "First law of thermodynamics" is also called as "law of conversation of energy". The formula for "First law of thermodynamics" of a system is that "change in internal energy of a system" is same as the difference of "heat energy" flows across the " boundaries of a system" and the "work done" on the system.

ΔU = Q - W

Q = ΔU + W

Where, "ΔU" is "change in internal energy", "Q" is "heat transferred and "W" is "work done.

Hence "Q = ΔU + W" is the equation is used to solve the questions related to "First law of thermodynamics".

To know more about the First law of thermodynamics follow

brainly.com/question/15071682

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2 years ago