Aparticle of mass m slides down, under gravity, a smooth ramp which is inclined at angle θ to the horizontal. at the bottom, it is joined smoothly to a similar ramp rising at the same angle θ to the horizontal to form a v-shaped surface. if the particle slides smoothly around the join, determine the period of oscillation, t, in terms of the initial horizontal displacement x from the centre join. note the shape of the potential well.

explanation:

earth's surface is mainly heated by the absorption of infrared radiation from the sun.

evaporation occurs because molecules in liquid water are warmed ( usually by the sun) and vibrate quicker, becoming less dense and rise.

condensation occurs because molecules in water vapor are cooled and therefore vibrate more slowly thus becoming more dense and eventually fall to earth.

lines of equal barometric pressure on a weather map are called: isobars : lines of equal temp on a weather map are called: isotherms.​

d. air pressure decreases as altitude increases.

i would say

+15-35=-20

going in opposite directions