How to calculate acceleration with sliding friction?
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If the mass of a crate is 50 kg and sliding friction is 250 N, what is the acceleration of the crate when the pulling force is 500 N?
Answer:
Hello Diana Diaz, the net force on the crate will be 500 - 250 = 250 N
Hence the acceleration a = F / m = 250 / 50 = 5 m/s^2
How to calculate how fast a liquid is cooling?
in
I was wondering about how to calculate how fast a liquid (Water for example) will cool from it's current temperature to for example fridge temperature?
There should also be a part of the equation addressing the size of the container
An example: a 1,5 litre bottle of water at 20°C (68°F) is put into a fridge - at 5°C (41°F). When will the water reach 5°C?
Thank you.
Answer:
This an extremely complex problem - no easy equation available.
If you control the process in some predictable fashion, you can make the calculations easier.
The problem involves the heat capacity of the fluid, the temperature difference between the fluid and the air above it, the heat capacity of the air above it, the fluid characteristics of the fluid to the extent that they relate to convection within the fluid, the flow of air across the top, if any, they thermal properties of the container holding the fluid, the thickness of the container, the temperature outside the container.
In a fridge, the problem also involves the control circuitry for the refrigerator, when the conmpressor turns on or off - and the temperature and thermal properties of everything in the refrigerator.
Good luck.
How to evaluate my methodology in Physics controlled assessment?
in
I've got my Physics controlled assessment later and I'm not sure about how to do this.
Answer:
More information required.
Probably best to ask your teacher/tutor/examiner.
How to find jump length by using speed and jump height?
in
I need help finding out the jump length of a person by only knowing the speed and jump height.
Let's say his speed is 10 (unkown identifier, probably km/h) and he jumps 1 meter up in the air. How far does he jump?
Answer:
First of all you have to divide motion in two: vertical and horiontal.
Start with the vertical one.
Vertical.
If you jump with a speed vo in an angle b, velocity in vertical axis, can be written as vyo=vo*sinb.
(y, o -indexes)
So in vertical direction there is an accelerated (decelerated to be more precise) motion.
A basic kinematic formula
vy=vyo+at
In this case a=g, besides it acts in an opposite direction, therefore
vy=vyo-gt
When you reach the highest point, vy=0
So, 0=vyo-gt => t=vyo/g=vo*sinb/g
This is the time, of reaching the summit.
Now use another kinematic formula.
y=voy*t+0.5*a*t Again, in our case
y=vo*sinb*t-0.5*g*t Use t calculated above.
h=vo*sinb*vo*sinb/g - 0.5*g*(vo*sinb)^2/g^2=(0.5*(vo)^2*(sinb)^2)/g
Since we know h and vo, from the formula find (sinb)^2=2gh/(vo)^2
(cosb)^2+(sinb)^2=1 => (cosb)^2=1-(sinb)^2
cosb=sqrt(1-2gh/(vo)^2))
Horizontal
In horizontal direction motion is unaccelerated. Horizontal component of speed is
vox=vo*cosb=vo*sqrt(1-2gh/(vo)^2))
A simple formula for distance, when a=0, is
x=vox*t=vo*sqrt(1-2gh/(vo)^2)) * vo*sinb/g=
=vo*sqrt(1-2gh/(vo)^2))*vo*sqrt(2gh)/(vo*g)=
=vo*sqrt(1-2gh/(vo)^2))*sqrt(2h/g)
How to create an earthquake with mobile phones?
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I was wondering if it is possible to create a vibration on earth with an amplitude of an earthquake if all mobile phones in the world vibrated (as in receiving calls) at the same time, same frequency, the same phase (or shifted phase) and same orientation.
Calculations, please. Suggestion: estimated number of mobile phones in the world x vibration amplitude / damping caused by human body, etc.
Answer:
You could google constructive and destructive interferance patterns but yes it might be possible to make seizmometers go off around the world with enough mobile phones set to vibrate at just the right point on the earth's surface. You would also need to check out the harmonics of the rocks though.
That has answered your question to fulfill the YA terms and conditions and earm me the two points but there is no way I'm doing complex calculations like that to satsify idle curiosity, because I don't care enough. Since you're interested so much you should do the research and perform the calculations yourself. That way you can be very confident of the results and you will learn a lot of physics and geology and maths at the same time.
How to tell if image formed by lens is larger or smaller, inverted or not by magnification?
in
Magnification = - p/s
So what if magnification = -0.2? Is that image BIGGER or SMALLER than the actual object? Is it inverted or not?
So basically what does the number 0.2 tell me? What does the negative symbol in front of 0.2 tell me?
ALSO, how do I know if it is upside down or not?
AND do convex mirrors ALWAYS form virtual images?
Answer:
You can refer to my free educational website of physics and math which I have created as a part of my hobby as under. The link to the page which answers your question is
http://schoolnotes4u.com/Physics%20(%20Std.%20XII%20)%20-%20Theory/10(T)%20-%20Ray%20Optics%20and%20Optical%20Instruments.pdf#page=16
Edit:
All your questions are answered in the table shown in the above link.
How to make available the energy required to improve rainfall distribution from pole to pole?
in
I mean, the sun unleashes a massive amount of energy at the equator leading to massive storms, torrential rain , cyclones and frequent widespread flooding while other places on Earth are faced with severe droughts.
Could we use the enormous energy cast by the sun on the equator to achieve this effect of improving rainfall distribution?
I am doing a research on this. Any suggestions would be greatly appreciated.
Thanks
Answer:
if a massive solar panel net work were built at the equator. then a massive amount of water gathered into an area where there is a drought. then you used the energy gathered at the equator to boil the water in the drought area to increase the humidity of the drought area and cause it to rain. in my opinion it is a ridiculous idea because there are many smarter methods not including solar power that can fix a drought. such as irrigation. technology would not have too much of a problem creating an aqua duct system.
How to calculate the velocity of light through the container?
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I am stuck on a physics problem and the question is "calculate the velocity of light through the container with water, based on your slope." My slope is 0.68. Can anybody show me the equation or how to solve this?!?!?!
Answer:
speed of light = 299 792 458 m / s
How to place ammeters and voltmeters in a circuit?
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In physics class, we've been doing circuits lately using the resistor and battery symbols. Now the teacher wants us to redraw the circuits using ammeter and voltmeter. I understand that ammeters are in-series and voltmeters are parallel, but idk how to draw that in the diagram :/ Can somebody explain or put up an example? Thank you!
Answer:
Connect Volt meter Parallel with both battery terminals (you know parallel lines | |)
Connect Ammeter series with one battery terminal and resistor(series ___ __ ___).
Battery terminals B1,B2
Volt meter V1,V2
Ammeter A1 A2
Resistor R1,R2
Connect B1V1R1, B2V2A1,A2R2
How to calculate the total kinetic energy released in an explosion?
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In an explosion, a 9 kg object which was initially at rest, spilts into three parts which all have equal mass. Two of the parts move apart with equal speeds of 12m/s and an angle of 50 degrees between their directions of motion. How much kinetic energy is released in this explosion?
Answer:
Write the total kinetic energy in terms of the momentums;
K = K1 + K2 + K3
K = P1^2/2m + P2^2/2m + P3^2/2m
Since the bomb was initially at rest you have the vector conservation of momentum eq;
P1 + P2 + P3 = 0
P3 = -P1 - P2
Square both sides (using dot product)
P3^2 = P1^2 + P2^2 - 2IP1IIP2ICos(50)
You have all the info. to calculate IP1I & IP2I and thus P1^2 & P2^2 and thus P3^2 which you can then put in the eq for K
EDIT__________________________________________________________________
That last term on the right should be +2IP1IIP2ICos(50) , not minus. Sorry about that.
