Homework Help

Is anyone else having issues with WA? I can log in, but it just continuously loads when I try to open an assignment.

Hi, I was wondering whether to calculate the potential difference, is V=Electrical energy/charge and V=kq/r for point charges whereas deltaV=electric field*radius. Can u give me a reason to why this is so if this is the case. Thanks!

Question: Three charges are placed at the corners of an equilateral triangle with sides of length 2.0 m. The three charges at the corners of the triangle at +4.0 X 10^-6 C, +2.0 X 10^-6 C, and -4.0 10^-6 C. Determine the electric potential at the midpoint of each side of the triangle. What I have done so far: So we know that the formula for electric potential is V=kq/r. So we can just use one of the charges to find the voltage. However, the answer differs depending on which of the 2 charges(which vertices you pick) for each charge. Thank you for taking the time to answer my question.

Hi, I was wondering how a Faraday cage works. Why is that that electric fields exist outside conductors and even on the surface of conductors but the field is always perpendicular to the surface of the conductor? Also, in relation to this topic, a conductor with an excess of negative charge is in electrostatic equilibrium. Describe the field inside the conductor. What does it mean for it to be in electrostatic equilibrium. Is it just that the electrons are on the surface of the conductor? if so, wouldn't the inside of the conductor be charged positive because a lot of the negative charge is no the surface. Thank you so much for those who take the time to answer…

Does anybody have any great ideas for how to do parts b-d? It seems like there should be a way to integrate the force of the spring, subtract the force of friction, do some math-o-magic, and pop out an answer. Or maybe look at the Uspring and work (hehe, puns) from there? It's (obviously) the fact that friction is non-conservative that makes the whole thing tough. Also- Kerbal Space Program makes doing homework really hard...

We are having trouble understanding the concept of question number 13 below: (we figured out the first ones OK) Base your answers to questions 9 through 13 on the information below. A manufacturer’s advertisement claims that their 1,250-kilogram (12,300-newton) sports car can accelerate on a level road from 0 to 60 miles per hour (0 to 26.8 meters per second) in 3.75 seconds. 9. Determine the acceleration, in meters per second2, of the car according to the advertisement. 10. Calculate the net force required to give the car the acceleration claimed in the advertisement. [show all work, including the equation and substitution with units.] 11. What is the …

I'm having trouble with question #9 for a it's just a simple normal force question with a block on an angle. So I did the usual mgcos(angle) = Fnormal and it didn't work. for b I used Fhor - mgsin(angle) = ma, solved for the acceleration and it also didn't work. I'm I missing something here?

I have no idea where to start for question 12. Any ideas?

Need help on a stubborn problem? Look for it here!

Can anyone help me with how to start 16? If the plane is flying horizontally, does the Vy initial = 0?

the problem reads a sudden stop, a car's seatbelt provides the force that stops the passenger. For a 80kg passenger, what's the seatbelt force if a car goes from highway speed of 90.0km/h to rest in 5.1s ?

A crane lifts a 225kg steel beam, applying a 2430N vertical force Find the net force on the beam Find the beam's acceleration

Has anyone gotten anywhere on problem 2 (a or b since one leads to the other)? I've made like five tables and I feel like if I could just figure out the first step I could get the rest of it to fall together... Even Cricket got bored watching me sit there trying it for a half hour

So for 16 on the WebAssign due tonight, I feel like I'm completely missing something. I algebra-ized two of the kinematics equations [ x=.5(vf+vo)t and vf=vo+at ] and got x=.5(2vo+at)t, hoping that then I could set the two rocks equal to each other because their x values are the same, and then solve for time somehow. This failed. Miserably. I looked a little bit at trying to set x=vot+.5at^2 equal to itself, again because the two x values should be the same, but didn't get anywhere. It feels like you have to make an equation equal to t, and then figure out a way to set that equal to itself (with one side adding the extra time until the second rock is thrown). Hope…

Hello! I'm a first time physics student (soon to be anyways, starting this September). For my summer homework I was tasked with learning about vectors. I am really stumped on adding more than 2 vectors. Anyways, the problem is: An object travels 20 miles easy, 10 miles south and then 15 miles west. A. Draw a vector diagram B. Find the objects displacement I would really appreciate an explanation for this problem!

How to calculate specific heat capacity of ice.specific latent heat of vapourisation of water,specific latent heat of fusion of ice, specific heat capacity of water? How will i know you have reply?

PLEASE HELP The charge on an electrons is -1.6x10 to the -19C. How many electrons are passing a given point in an electric circuit each second will give rise to a current of 4.0A? My answer is: Q=Ixt -1.6x10^-19=4.0xt 4.0xt=-1.6x10^-19 =-1.6x10^-19x-6.2 divide by 4.0 =2.48x10^-19 or 2.5x10^-19

Hi, For the Physics C Mech test, do we need to memorize Moment of Inertia equations for the various objects (rod, sphere, etc?) Will the problems you demonstrated in your videos appear on the multiple choice portion? They seem to be pretty complicated for the MC questions. Thanks!

hi, i know i posted this question in response to your retarding forces video ( ), but per your advice i created an account here. anyway, do you think it is advisable just to memorize the equation you derived? or will the AP Phys. C test make you figure it out on your own? will i just need to plug in numbers? (In other words, what stuff from the video do I actually need to keep in my head? how will i use it?) sorry for so many questions; an answer such as "know how to derive them" or "you don't need to memorize any of it" or "just plug in numbers" will do! thanks again!

internet the formula shows as this: Vt=squs of(2W/Cd.A.p) >> where as Vt is terminal velocity. W is weight. Cd is the coeficient of >> the object mass, A is the frontal area of the affect area, p is the air >> density. >> Can't it be used to find out the terminal velocity?. Is that right??? To find an object's terminal velocity from free falling.

3.90 ... CP A rocket designed to place small payloads into orbit is carried to an altitude of 12.0 km above sea level by a converted airliner. When the airliner is flying in a straight line at a constant speed of 850km/h, the rocket is dropped. After the drop, the airliner maintains the same altitude and speed and continues to fly in a straight line. The rocket falls for a brief time, after which its rocket motor turns on. Once its rocket motor is on, the combined effects of thrust and gravity give the rocket a constant acceleration of magnitude 3.00g directed at an angle of 30 degree above the horizontal. For reasons of safety, the rocket should be at least 1.00…

Q:A tennis ball is served horizontally from 2.4m above the ground at 30m/s (a)The net is 12m away and 0.9m high, will the ball clear the net? (b)Where will the ball land? :sorrow:

A rock is thrown downward from the top of a 40.0-m-tall tower with an initial speed of 12 m/s. Assuming negligible air resistance, what is the speed of the rock just before hitting the ground? i asked this question somewhere else, but i still don't understand how to do it, the person told me to "Make assumptions like negligible air resistance, starting velocity is zero. Combining and rearranging the equations:" Ek = 1/2mv^2 Eg = mg(delta)h but i do not know where to put what in. the only thing i did was i draw the diagram, i have no idea what else to do. can you please explain how to do this. thank you

A mass of 40tonnes is accelerated from rest for 20s then runs uniformly for 5 mins and is finally brought to rest. Assuming acceleration and deceleration are 0.7m/s2 calculate; a) total distance travelled) b)total force required during this period (ignoring friction) for a I have calculated 4480m for b I have calculated 28kn. (F=m x a = 40000 x0.7)

Hi, the question is...a body of mass 200kg is raised to a height of 5m before being allowed to fall freely. Calculate the potential energy and kinetic energy; a) before it starts to fall when it reaches the ground. i have calculated for P.E@5m = PE=m x g x h = 200x10x5 = 10kJ P.E@0m= m x g x h = 200x10x0= 0J k.e@5m= ke= (m x v2)/2 = (200x0)/2 = 0J k.e @0m= (m x v2)/2 = (200x10sq)/2 = 10KJ