When you swim in a pool, select one: a. rolling friction occurs. b. fluid friction occurs. c. sliding friction occurs. d. static friction occurs.

Aperson walking 1 mile everyday for exercise, leaving her front porch at 9: 00 am and returning to her front porch at 9: 25 am. what is the total displacement of her daily walk? a) 1 mileb) 0c) 25 minutes d) none of the above

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

Aprotein molecule in an electrophoresis gel has a negative charge. the exact charge depends on the ph of the solution, but 30 excess electrons is typical. what is the magnitude of the electric force on a protein with this charge in a 1600n/c electric field? write in two significant numbers, and also in newton