A hot air balloon contains 85,000 moles of air. To what temperature must the

Which describes a train’s acceleration if it changes speed from 25 m/s to 10 m/s in 240 s? positive acceleration no acceleration

OLEGan [10]

To understand acceleration, you need to know speed and velocity.

Why?

Acceleration is the change in velocity, and the velocity equation is:

velocity = distance / time Units: (m/s)

If a change in position means an object has a velocity, then that means that a change in velocity has an acceleration (I recommend you look at the graphs, it will help a lot to understand the relationship between each).

Now that we have some background, lets use it to answer the problem!

The change in velocity is from 25 m/s to 10 m/s, and we have a time. Lets plug it into the (average) acceleration equation so we can visualize it better!

The symbol delta means "change" : Δ

a = Δv / Δt

expanded to:

a = vf - vi / tf - ti

(vf = velocity final, vi = velocity initial, tf = time final, ti = time initial)

So if the train's speed went from 25 m/s to 10 m/s, then that means that 10 m/s is our final velocity and 25 m/s is the initial:

a = 10 - 25 / 240

a = -15 / 240

a = -0.0625 m/s^2

Since we ended up with a negative number, it means that the train has a negative acceleration!!!!!

The fast way to do this:

25 m/s is bigger than 10 m/s, so that means that to go from 25 m/s to 10 m/s you have to slow down--otherwise known as putting on your brakes. So if the change in speed is negative then the acceleration will be negative.

In other words, if your final speed is less than your initial speed then your acceleration would be negative.

Sorry for the long explanation! I hope you never struggle with this again though!

Hope it helped,

3 0

3 years ago

Find the intensity of electromagnetic radiation at the surface of the sun (radius r=R=6.96×105kmr=R=6.96×105km). Ignore any scat

alisha [4.7K]

Answer:

$I = 4.46*10^{16}W/m^2$ .

Explanation:

Intensity $I$ of the electromagnetic radiation is given by

$I = \dfrac{P}{4\pi r^2},$

where $r$ is the distance from the EM source (the center of the sun, in our case), and $P$ is the power output of the sun and it has the value

$P = 3.9 *10^{26}W.$

Since the radius of the sun in meters is $r = 6.96*10^8km$ , the intensity $I$ of the electromagnetic radiation at the surface of the sun is

$I = \dfrac{3.9*10^{26}W}{4\pi (6.96*10^8m)^2}\\\\\boxed{ I = 4.46*10^{16}W/m^2}$

The intensity of the electromagnetic radiation at the surface of the sun is $I = 4.46*10^{16}W/m^2$ .

7 0

3 years ago

How much force is needed to stretch a spring 1. 2 m if the spring constant is 8. 5 N/m? 7. 1 N 7. 3 N 9. 7 N 10. 2 N.

statuscvo [17]

The amount of force required to stretch or compress the spring is known as the spring force. Its unit is Newton(N). Force is needed to stretch spring is 10.2 N.

<h3>What is spring force?</h3>

The force required to extend or compress a spring by some distance scales linearly with respect to that distance is known as the spring force. Its formula is

F = kx

The given data in the problem is;

F is the spring force =?

K is the spring constant= 8.5 N/m

x is the length by which spring got stretched = 1.2m

$\rm F_S=Kx \\\\ \rm F_S=8.5 \times 1.2 \\\\ \rm F_S=10.2 N$

Hence the force is needed to stretch the spring is 10.2 N.

To learn more about the spring force refer to the link;

brainly.com/question/4291098

6 0

2 years ago

If a 400-mm diameter pipe with a pipe roughness coefficient of 100 flows full of pressurized water with a head loss of 0.4 ft pe

RoseWind [281]

Answer:

Q = 913.9 gpm

Explanation:

The Hazen Williams equation can be written as follows:

$P = \frac{4.52\ Q^{1.85}}{C^{1.85}d^{4.87}}$

where,

P = Friction Loss per foot of pipe = $\frac{0.4}{1000\ ft}$ = 4 x 10⁻⁴

Q = Flow Rate in gallon/min (gpm) = ?

d = pipe diameter in inches = (400 mm)(0.0393701 in/1 mm) = 15.75 in

C = roughness coefficient = 100

Therefore,

$4\ x \ 10^{-4} = \frac{4.52\ Q^{1.85}}{(100)^{1.85}(15.75)^{4.87}}\\\\Q^{1.85} = \frac{4\ x \ 10^{-4}}{1.33\ x\ 10^{-9}} \\\\Q = (300384.75)^\frac{1}{1.85}$

5 0

3 years ago

What will be the ratio between the initial and final kinetic energy of a car, if its velocity is tripled?

Katarina [22]

Answer:b

Explanation:

7 0

2 years ago