Recent content by ACPower

I think the problem you want to consider is something like this: Consider that the point of contact with the obstacle and the wheel is now a pivot point, and you want the motor to supply enough torque to lift the entire cart, using the radius of the wheel as the length of the lever. This only...

Top physicists are able to create high enough voltages to ionize air simply by padding around in their socks on the carpet in the dry winter air, then touching a grounded conductor.

I think you can just record the initial (level) value for the 'down' vector, then just use the dot product of that vector with later down vectors to get the cosine of the angle of the vehicle. For a car you can assume that all of the angle is front-to-back tilt.

My 'Instantaneous Angular Velocity' is probably a non-rigorous bookkeeping trick. I would try to just take the linear velocity of the CoM just before contact and use it for the angular velocity, which would just be V/r. You should probably use just the component of the linear velocity...

You want to calculate the torque, the rotational equivalent of a force, that arises when the collision occurs and the Center of Mass starts rotating around the point of impact, which is (temporarily) fixed. The magnitude of the torque is the change in angular momentum, and is the force times the...

"White" light is typically classified based on an idealized black body spectrum of wavelength intensities for a given temperature, in Kelvin. For example, photographers talk of 6500Kelvin as 'daylight'.

If the height is Y, and you are on Earth where the acceleration due to gravity, g, is 9.8m/s^2: Y = 0.5*g*t^2 so the time, t is: t = sqrt(2*Y/g) which will be less than 1s. So you would need to throw faster than 60ft/s, or 40mph.

If the ball reaches the top of its trajectory in the middle, you know it will have at most the time it takes to to fall from ceiling to floor to reach the other side. Calculate that time and you can know the horizontal velocity the throw would need. The total velocity will not be much more than...

The coefficient is 0.9, since you measured h2/h1 to be 0.81, and V2/V1 = sqrt(h2/h1) = sqrt(0.81) = 0.9

You can't know that unless you know the polarization of the light before it reaches the polaroid filter, so you either need to know the polarization of your light source, or pass it through a known polarizing filter beforehand.

Most photovoltaics have a single optimal photon wavelength whose energy corresponds to the 'band gap' of the material. The band gap is the voltage between the free electrons in the conduction layer and the bound electrons in the material. Photons with energy less than this band gap cannot be...

A personal thought experiment on classical entanglement: Consider a sock draw with N pairs of different colored socks, with each pair clipped together. Alice closes her eyes, takes out a pair, unclips the socks, and puts one in each of two waiting brown lunch bags. She then hands one bag to Bob...

Wouldn't a basic answer to the question be something like: Build an LC oscillator circuit with the correct capacitors and inductors, hook it to a dipole antenna of the right length, then drive/watch the voltage to send/receive radio waves. Calculations for the antenna, L and C are left as...

Well you know the final pressure will be, in your example 25lbs divided by the area (4 square ft). You can also assume the pressure times volume remains constant, so if the area A is 4sq.ft , then A*100ft*(initial pressure) = A*(final height)*Pressure. Cross off those As and: final height =...

The top tank will drain first, since the tanks below it would be refilled from the tank above, were their levels to go down.