A cyclist and bicycle have a combined mass of 90 kg. Starting from rest, the cyclist rides down a 10 m high hill and up a 7 m high hill without pedaling the bicycle.
What is the potential energy of the cyclist and bicycle at the top of the 7 m hill with respect to the bottom of the 7 m hill?

Suppose that an electromagnetic wave which is linearly polarized along the x−axis is propagating in vacuum along the z−axis. the wave is incident on a conductor which is placed at z > 0 region of the space. the conductor has conductivity σ, magnetic permeability µ and electric permittivity ε. (a) find the characteristic time for the free charge density which dissipates at the conductor. (b) write the maxwell equations and derive the wave equation for a plane wave propagating in a conductor. (c) find the attenuation distance at which the incident amplitude reduces to e ^−1 of its initial value. (d) find the electric and magnetic fields inside the conductor. 8 (e) find the power loss per area of the incident electromagnetic wave at the surface of conductor.

What is a subatomic particle with a negative charge and very little mass?

In a system with only a single force acting upon a body, what is the relationship between the change in kinetic energy and the work done by the force? answers: work is equal to the change in kinetic energy. work depends on the square of the change in potential energy. work is equal to the negative of the change in kinetic energy. work is equal to the square of the change in kinetic energy