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3 years ago

What does it mean if a paint sample "matches" a known sample from a vehicle? Does this indicate the same source? Why or why not?

1 answer:

4 0

It wouldn't indicate the same source if the paint was from a different place. If the paint was the same brand and color it would be but if not then no

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Suppose you increase your walking speed from 7 m/s to 15 m/s in a period of 2 m. What is your acceleration?

likoan [24]

Acceleration = (change in speed) / (time for the change)

Change in speed = (end speed) - (start speed) = (15 m/s - 7 m/s) = 8 m/s

time for the change = 2 minutes = 120 seconds

Acceleration = (8 m/s) / (120 seconds)

Acceleration = 0.067 m/s²

7 0

3 years ago

A sled of mass 2.12 kg has an initial speed of 5.49 m/s across a horizontal surface. The coefficient of kinetic friction between

Darya [45]

Answer:

The speed of the sled is 3.56 m/s

Explanation:

Given that,

Mass = 2.12 kg

Initial speed = 5.49 m/s

Coefficient of kinetic friction = 0.229

Distance = 3.89 m

We need to calculate the acceleration of sled

Using formula of acceleration

$a = \dfrac{F}{m}$

Where, F = frictional force

m = mass

Put the value into the formula

$a=\dfrac{\mu mg}{m}$

$a=\mu g$

$a=0.229\times9.8$

$a=2.244\ m/s^2$

We need to calculate the speed of the sled

Using equation of motion

$v^2=u^2-2as$

Where, v = final velocity

u = initial velocity

a = acceleration

s = distance

Put the value in the equation

$v ^2=(5.49)^2-2\times2.244\times3.89$

$v=\sqrt{(5.49)^2-2\times2.244\times3.89}$

$v=3.56\ m/s$

Hence, The speed of the sled is 3.56 m/s.

8 0

3 years ago

What is the suitable condition for the superconductivity and high resista (a) Weak phonon-phonon interactions (b) No interaction

Readme [11.4K]

Answer:

(d) A strong electron-phonon interaction

Explanation:

Superconductivity -

The phenomenon of superconductivity is due to the attractive force between electrons from the exchange of the phonons that cause the bound pair of electrons known as cooper pairs .

A strong electron -phonon intercation is suitable condition for superconductivity and high resistance .

4 0

2 years ago

10. Electrical Power: Why do our electronic devices get hot? We know

Vesna [10]

Answer:

Now, think on the electrons flowing through a conductor (we can think on the resistor as a simple conductor, like a piece of metal)

Inside the conductor, we have some "fixed" (they do not flow with the current) electrons, such that as the current flows in the conductor, the flowing electrons can interact with the fixed ones in the conductor. Then we can have collisions inside the conductor.

In those collisions, the flowing electrons leave energy in the conductor, and as we know, heat is a form of energy. Then when we have a lot of these collisions, the temperature of the conductor increases.

That is why electronic devices get hot.

Also, as the temperature of a conductor increases, the electrons inside of it start to move more, then the probability of an interaction with the flowing electrons increases.

3 0

2 years ago

A water pipe having a 4.00 cm inside diameter carries water into the basement of a house at a speed of 1.00 m/s and a pressure o

posledela

Answer:

$8.16\ \text{m/s}$

Explanation:

$d_1$ = Initial diameter = 4 cm

$v_1$ = Initial velocity = 1 m/s

$d_2$ = Final diameter = 7.8 m

$v_2$ = Final velocity

$A$ = Area = $\pi\dfrac{d^2}{4}$

From the continuity equation we get

$A_1v_1=A_2v_2\\\Rightarrow \pi\dfrac{d_1^2}{4}v_1=\pi\dfrac{d_2^2}{4}v_2\\\Rightarrow v_2=\dfrac{d_1^2}{d_2^2}v_1\\\Rightarrow v_2=\dfrac{4^2}{1.4^2}\times 1\\\Rightarrow v_2=8.16\ \text{m/s}$

The speed of water at the second floor is $8.16\ \text{m/s}$ .

8 0

2 years ago