Wood burning is a chemical reaction. However, wood does not just spontaneously catch on fire. It needs to begin the chemical reaction.

A) Chemical Energy
B) Physical Energy
C) Electron Energy
D) Activation Energy

When an object is heated it contracts. a. true b. false

What are the starting materials for nuclear fission? two small nuclei two large nuclei a neutron and a large nucleus a neutron and a small nucleus

Rank the six combinations of electric charges on the basis of the electric force acting on q1. define forces pointing to the right as positive and forces pointing to the left as negative. rank positive forces as larger than negative forces. q1,q2,q3 = positive(+) q1 = + q2 = + q3 = - q1 = + q2= - q3= + q1= - q2= + q3= + q1= + q2= - q3= - q1,q2,q3 = negative