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liraira [26]
3 years ago
12

A car traveling at 20 m/s starts to decelerate steadily. It comes to a complete stop in 7 seconds. What is it’s acceleration?

Physics
1 answer:
Yuki888 [10]3 years ago
6 0
I think the answer is -2.9m/s2.
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Consider an electron with charge −e and mass m orbiting in a circle around a hydrogen nucleus (a single proton) with charge +e.
alexandr1967 [171]

Answer:

v=\sqrt{k\frac{e^2}{m_e r}}, 2.18\cdot 10^6 m/s

Explanation:

The magnitude of the electromagnetic force between the electron and the proton in the nucleus is equal to the centripetal force:

k\frac{(e)(e)}{r^2}=m_e \frac{v^2}{r}

where

k is the Coulomb constant

e is the magnitude of the charge of the electron

e is the magnitude of the charge of the proton in the nucleus

r is the distance between the electron and the nucleus

v is the speed of the electron

m_e is the mass of the electron

Solving for v, we find

v=\sqrt{k\frac{e^2}{m_e r}}

Inside an atom of hydrogen, the distance between the electron and the nucleus is approximately

r=5.3\cdot 10^{-11}m

while the electron mass is

m_e = 9.11\cdot 10^{-31}kg

and the charge is

e=1.6\cdot 10^{-19} C

Substituting into the formula, we find

v=\sqrt{(9\cdot 10^9 m/s) \frac{(1.6\cdot 10^{-19} C)^2}{(9.11\cdot 10^{-31} kg)(5.3\cdot 10^{-11} m)}}=2.18\cdot 10^6 m/s

7 0
4 years ago
please help me guys please please please please please please please please please please please please please​
seropon [69]

Answer:

1.F = 256 N

2.a = 8 m/s/s

By looking at the given information, you know force, and an acceleration. Therefore you have enough information to use the first formula.

F = ma

256 N = m * 8 m/s/s

m = 256 N/8 m/s/s

m = 32 Kg

6 0
3 years ago
Please tell me why the answer is zero
Oduvanchick [21]

This question is checking to see whether you understand the meaning
of "displacement".

Displacement is a vector: 

-- Its magnitude (size) is the distance between the start-point and
the end-point, no matter what route might have been followed along
the way.

-- Its direction is the direction from the start-point to the end-point.

Talking about the Earth's orbit around the sun, we can forget about
the direction of the displacement, and just talk about its magnitude
(size).

If we pretend that the sun is not moving and dragging the whole
solar system along with it, then what do we see the Earth doing
in one year ? 
We mark the place where the Earth is at the stroke of midnight
on New Year's Eve.  Then we watch it as it swings around through
this gigantic orbit, all the way around the sun, and in a year, it's back
to the same point that we marked ! 

So what's the magnitude of the displacement in exactly one year ?
It's the distance between the start-point and the end-point.  But the
Earth came back to the same place it started from, so there's no
separation at all between the start-point and the end-point. 
The Earth covered a huge distance in that year, but the displacement
is zero.

5 0
3 years ago
Read 2 more answers
A 12-kg object is moving rightward with a constant velocity of 4 m/s. How much net force is required to keep the object moving w
Nadusha1986 [10]
C an s and yes ihavetotypemore
3 0
3 years ago
A mass of gas under constant pressure occupies a volume of 0.5 m3 at a temperature of 20°C. Using the formula for cubic expansio
Tanzania [10]
Without a change in pressure

V/T = V/T
Before change = after change - expansion

x = volume at m3

(0.5)/20 = x/45

.025 = x/45

.025 * 45 = x

1 = x

The volume of this gas is 1 m3.

Hope this helps :) also the gas expanded .5 of m3.



4 0
3 years ago
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