All of the following are evidence that a chemical reaction has occurred except . a new substance formed
a new substance formed

a change in temperature occurred
a change in temperature occurred

gas bubbles form
gas bubbles form

matter changes state

This problem has been solved! see the answera non-uniform fire escape ladder is 6.0m long whenextended to the icy alley below. it is held at the top by africtionless pivot, and there is neglibible frictional force fromthe icy surface at the bottom. the ladder weighs 250n, and it'scenter of gravity is 2.0m along the ladder from the bottom. amother and child of total weight 750n are on the ladder 1.5m fromthe pivot. the ladder makes an angle θ with the horizontal.find the magnitude and direction ofa) the force exerted by the icy alley on the ladderb) the force exerted by the ladder on the pivotc) do your answers in part a and b depend on the angle?

Arock collection comes from which part of earth?

Zeros that follow non-zeros numbers and are also to the right of a decimal point are significant