If a 50 kg student is pushed in a rolling chair with a force of 20 N, what is the student’s acceleration? 2.5 m/s2
4 m/s2
1,000 m/s2
0.4 m/s2

Awhite powder is added to a solution. the images show observations made before the powder is added, just after the powder has been added, and a little while later. (the liquid in the small beaker is phenol red solution.) what evidence shows that a chemical change has taken place?