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3 years ago

A car's velocity changes from 40 m/s to 30 m/s in 40 seconds. What is the

Physics

1 answer:

valina [46]3 years ago

7 0

Answer:

- 0.25m/s²

Explanation:

Given parameters:

Initial velocity = 40m/s

Final velocity = 30m/s

Time taken = 40s

Unknown:

Acceleration of the car = ?

Solution:

Acceleration is the rate of change of velocity with time.

So;

Acceleration = $\frac{Final velocity - Initial velocity }{time }$

Acceleration = $\frac{30 - 40}{40}$ = - 0.25m/s²

This implies that the car will decelerate at a rate of 0.25m/s²

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HOLA, NECESITO AYUDA!

givi [52]

The electrostatic force between the two ions is $2.9\cdot 10^{-10} N$

Explanation:

The electrostatic force between two charged particle is given by Coulomb's law:

$F=k\frac{q_1 q_2}{r^2}$

where

$k=8.99\cdot 10^9 Nm^{-2}C^{-2}$ is the Coulomb's constant

$q_1, q_2$ are the two charges

r is the separation between the two charges

In this problem, the ion of sodium has a charge of

$q_1 = +e = +1.6\cdot 10^{-19} C$

while the ion of chlorine has a charge of

$q_2 = -e = -1.6\cdot 10^{-19}C$

And the distance between the two ions is

$r=282 pm = 282\cdot 10^{-12} m$

Substituting, we find the electrostatic force between the two ions:

$F=(8.99\cdot 10^9) \frac{(1.6\cdot 10^{-19})(-1.6\cdot 10^{-19})}{(282\cdot 10^{-12})^2}=-2.9\cdot 10^{-10} N$

where the negative sign simply means that the force is attractive, since the two ions have opposite charge.

Learn more about electrostatic force:

brainly.com/question/8960054

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6 0

3 years ago

Your new motorcycle weighs 2450 N.

Snowcat [4.5K]

Answer:

Mass can never be negative. Everything has mass. Just like how they ask you to find area under the graph in maths. If the area is in the 3rd and 4th quadrant, when calculated, you would get negative answer.However, area can not be negative because it is a place/ location. It's exactly the same as mass.

4 0

2 years ago

What can always be said about a negatively-charged ion?

KiRa [710]

Answer: A negatively-charged ion always has more electrons than protons

Explanation:

First, we know that the elementary negative charge is the electron, while the positive one is the proton. Such that both have the same charge in magnitude, but a different sign. Such that if we have the same number of electrons and protons in an atom, the charge of this atom will be neutral.

And an ion is an atom with a different number of electrons and protons, so the charge of the atom is not neutral.

Then if we have a negatively-charged ion, the charge of this atom is negative. Then we must have a larger number of electrons (the negative ones) than protons (the positive ones)

Then the correct option is:

A negatively-charged ion always has more electrons than protons

5 0

3 years ago

On a sunny day, a student poured a cup of water on the sidewalk to make a puddle. When he returned later, the puddle was gone. T

ivanzaharov [21]

Answer:

The students conclusion is wrong.

Explanation:

The students conclusion is wrong because liquids can not soak into concrete. The water evaporated because it was a hot sunny day. The water turned into a gas called water vapor.

8 0

3 years ago

Two liquids, A and B, have equal masses and equal initial temperatures. Each is heated for the same length of time over identica

DochEvi [55]

Answer:

So the specific heat of the liquid B is greater than that of A.

Explanation:

Liquid A is hotter than the liquid B after both the liquids are heated identically for the same duration of time from the same initial temperature then according to heat equation,

$Q=m.c.\Delta T$