A sled is lifted to a height of 20 m on the slope and the mass of the rider is 65 kg. If gravity is a constant at 10 m/s2 calculate the following GPE at the highest point (GPE = mgh).
If energy is conserved in a system how much KE would this same sled and rider have at the lowest point.
At what position on the hill would the sled and rider have exactly half the total amount of energy?

The activity series is shown in the attached picture. if the element is below the other, then you can displace the other. following the activity series as a guide, the reactions are as follows: nickel and aluminum chloride3 ni + 2 alcl₃  → 3 nicl₂ + 2 albarium and copper bromideba + cubr  →  no reaction because cu is less oxidizable than bapotassium nitrate and aluminum3 kno₃ + al  → al(no₃)₃ + 3 ksodium phosphate and zincnaso₄ + zn  → znso₄ + na

The correct answer should be "electrons orbit the nucleus in circular motions exactly as shown on the classic bohr model."