Suppose an object's initial velocity is 10 m/s and its final velocity is 4 m/s. mass is constant.
what can best be concluded about the object based on the work-energy theorem?
o work is positive, the environment did work on the object, and the energy of the system increases.
work is positive, the object did work on the environment, and the energy of the system increases.
work is negative, the object did work on the environment, and the energy of the system decreases.
work is negative, the environment did work on the object, and the energy of the system decreases.

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.

Alead ball is dropped into a lake from a diving board 5m above the water . it hits the water with a certain velocity and then sink with constant velocity in bottom . it reaches the bottom 5 second after it is dropped if g= 10m/s2 . find depth of the lake and average velocity of the ball ?

What is the measure of a change in an objects velocity?