A battery powered toy car accelerates from 0.0 m/s to 8.5 m/s. Its mass is 0.55 kg. The chemical store in its battery is decreased by 30 J.
Calculate the efficiency of this process.

Aproton is projected toward a fixed nucleus of charge +ze with velocity vo. initially the two particles are very far apart. when the proton is a distance r from the nucleus its velocity has decreased to 1/2vo. how far from the nucleus will the proton be when its velocity has dropped to 1/4vo?

The most important difference between a wedge and an inclined plane is a. their size b. their shape c. how they are used d. what they are made of

In a stagnant pool of water, a crayfish may spend much of its time lying with one side of its carapace near the surface of the water. in this position, it will move the walking legs on that side in a rhythmic back-and-forth motion. explain the likely function of this behavior.