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1 year ago

While working out, a man performed 500 J of work in 8 seconds. What washis power?A. 4000 WB. 62.5 WC. 500 WD. 38.5 W

Physics

1 answer:

Sav [38]1 year ago

5 0

Given:

The work done by the man is W = 500 J

The time taken by the man is t = 8 s

To find the power.

Explanation:

The power can be calculated by the formula

$P=\frac{W}{t}$

On substituting the values, the power will be

$\begin{gathered} P=\text{ }\frac{500}{8} \\ =\text{ 62.5 W} \end{gathered}$

Thus, the power is B. 62.5 W

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A car driver traveling at a speed of 108km per hour ,sees a traffic light and stopped after travelling for 20seconds .Find the a

navik [9.2K]

Answer:

– 2.5 m/s²

Explanation:

We have,

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• Final velocity, v = 0 m/s (it stops)

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We have to find acceleration, a.

$\longrightarrow$ a = (v ― u)/t

$\longrightarrow$ a = (0 – 50)/20 m/s²

$\longrightarrow$ a = –50/20 m/s²

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$\longrightarrow$ a = – 2.5 m/s² (Velocity is decreasing) [Answer]

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2 years ago

An electron is released from rest at a distance of 6.00 cm from a proton. If the proton is held in place, how fast will the elec

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Answer:

91.87 m/s

Explanation:

<u>Given:</u>

x = initial distance of the electron from the proton = 6 cm = 0.06 m

y = initial distance of the electron from the proton = 3 cm = 0.03 m
u = initial velocity of the electron = 0 m/s

<u>Assume:</u>

m = mass of an electron = $9.1\times 10^{-31}\ kg$
v = final velocity of the electron
e = magnitude of charge on an electron = $1.6\times 10^{-19}\ C$

p = magnitude of charge on a proton = $1.6\times 10^{-19}\ C$

We know that only only electric field due to proton causes to move from a distance of 6 cm from proton to 3 cm distance from it. This means the electric force force does work on the electron to move it from one initial position to the final position which is equal to the change in potential energy of the electron due to proton.

Now, according to the work-energy theorem, the total work done by the electric force on the electron due to proton is equal to the kinetic energy change in it.

$\therefore \textrm{Kinetic energy change}= \textrm{Change in potential energy}\\\Rightarrow \dfrac{1}{2}m(v^2-u^2)= \dfrac{kpe}{y}-\dfrac{kpe}{x}\\\Rightarrow \dfrac{1}{2}m(v^2-(0)^2)= \dfrac{kpe}{0.03}-\dfrac{kpe}{0.06}\\\Rightarrow \dfrac{1}{2}mv^2= \dfrac{100kpe}{3}-\dfrac{100kpe}{6}\\\Rightarrow \dfrac{1}{2}mv^2= \dfrac{100kpe}{6}\\$

$\Rightarrow v^2= \dfrac{100kpe\times 2}{6m}\\\Rightarrow v^2= \dfrac{100kpe}{3m}\\\Rightarrow v^2= \dfrac{100\times 9\times 10^9\times 1.6\times 10^{-19}\times 1.6\times 10^{-19}}{3\times 9.1\times 10^{-31}}\\\Rightarrow v^2=8.44\times 10^3\\\Rightarrow v=91.87\ m/s\\$

Hence, when the electron is at a distance of c cm from the proton, it moves with a velocity of 91.87 m/s.

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3 years ago

The distance from earth to teh sun usb approxximately 93 million miles. a scientist would write that number as

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A scientist would write that number as 1.49 x 10⁸ kilometers .

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M=3000km v=25m/s what’s the momentum

valina [46]

<h3>Answer:</h3>

Momentum of the given body will be : 75000 Kg m/s

<h3>Explanation:</h3>

According to Newton's first law of motion, all bodies continue to be in the state of rest or motion unless an external force is applied on the body. We can use this in the case of momentum also

The formula of momentum is given by :

$:\implies \sf\quad \sf \: P = mv$

Here, we are given the mass of the body ( m ) as 3000kg and the velocity of the body ( v ) as 25 m/s. On putting the values in the formula:

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