Which of the following situations best demonstrates the effects of friction? a parachutist descending to the ground
a loaded slingshot
an apple falling from a tree
two trucks colliding

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.

Given the position vector of the particle r(t)=(t+1)i+(t^2−1)j+2t k, find the particle's velocity and acceleration vectors at t=1

Acombination reaction is when two or more combine to form one product. a decomposition reaction is when a substance breaks down into two or more simpler substances in a chemical reaction.