We have been given practices tests with answers and I have been at this for hours and I can’t get the same answer that my teacher has given us which is:
Ez= -(100z + 100/z^2)

I have tried this every which way and can’t get it.

The electric potential along the z-axis is given by
V(z) = 50 z2 V/m2
– 100/z Vm,
where z is given in meters. Give an expression for Ez(z).

Posted by James Malone

Hi, I need a software or an apparatus (available in school conditions) to measure wavelengths of visible light. In my lab I use coloured filters to get different colours of light, but I have to measure exact wavelengths.
Thank you in advance

Vanja posted

Answer:

The wavelength may be measured by Diffraction grating experiment, Newton’s rings experiment etc.

http://practicalphysics.org/measuring-wavelength-light.html

http://vlab.amrita.edu/?sub=1&brch=189&sim=1106&cnt=1

A person is born on point A and dies on point B, point A = point B. What is her/his average velocity?

I know that the answer should be 0, but is there any possibility for the person’s average velocity to be any number that isn’t 0? Her/His displacement is 0, so her/his average velocity should also be 0, but I have people arguing that it is possible for the person’s average velocity to not be 0, or that there is not enough information provided in the question to solve for the answer.

Posted by Jack

Answer:

If you consider with respect to earth only, then the answer is zero. But if the point of reference is outside the earth, then the answer will be different. If the frame of reference is outside the solar system, or milky way galaxy then the answer will be different again.

THINK OF IT

There is a species of bug on the planet Mindbender called bugonians than can only hear over the frequency of 290Hz. Bugonians are blind and relies only on hearing to survive. The mass of Mindbender is 7.66 x10^25 kg and a radius of 2.46 x10^7m.
A pendulum with a frequency of 0.41Hz attached to the ceiling above the top of a miniature rollercoaster. The bob on the pendulum has a mass of 2.0 kg. It hits a toy cart with a weight of 4.0N at the top of a track, which is touching a spring, with a spring constant of 2.6N/m. It is positioned 0.15m from equilibrium when it rolls down the hill.
The height of the first hill is unknown, but it is equal in height to the first loop of the rollercoaster. The minimum velocity to keep the cart in the first loop is 1.656 m/s.
After the first loop, the cart moves up a ramp with a coefficient of friction of 0.009. The cart is producing a noise at the frequency of 250Hz. The ramp has a height of 0.20 m, where it drops off and the cart is launched as a projectile.
There is a Bugonian suntanning 4.6m from the end of the ramp. Can the Bugionian hear the approaching cart, if you consider the Doppler effect on the frequency of sound as the cart is hurdling through Minderbender space towards him?
You must assume complete energy conversions UNLESS there is friction

Posted by Sam

​You are arguing over a cell phone while trailing an unmarked police car by 25.0 m; both your car and the police car are traveling at 120 km/h. Your argument diverts your attention from the police car for 2.0 s (long enough for you to look at the phone and yell,“I won’t do that!”). At the beginning of that 2.0 s, the police officer begins braking suddenly at 5.05 m/s2. (a) What is the separation between the two cars when your attention finally returns? Suppose that you take another 0.500 s to realize your danger and begin braking. (b) If you too brake at 5.05 m/s2, what is your speed when you hit the police car?

Posted by Fardhokt

F​rom: nileshnegi

Subject: kinematics

Message Body:
on a 2 lane road,car A is travelling with a speed of 36 km/hr 2 cars B n C approach car A  in opposite direction with a speed of 54km/hr each. at a certain instant when distance AB is equal to AC both bieng 1 km.. B decide to over lap A before C does . what minimum of acc of car  B is required to avoid an accident with car A?