How can i interest my students in chemical and physical changes in matter?

Aproton is projected toward a fixed nucleus of charge +ze with velocity vo. initially the two particles are very far apart. when the proton is a distance r from the nucleus its velocity has decreased to 1/2vo. how far from the nucleus will the proton be when its velocity has dropped to 1/4vo?

Determine the maximum r-value of the polar equation r =3+3 cos 0

Acompound machine is also called a machine. a. force b. simple c. complex d. directional