What is a property of “normal force”? a. It always points perpendicular to the contact surface. b. It always points parallel to the contact surface. c. It always points up. d. It always completely counters gravity.

What is the earliest point in the universe that we can observe? why can’t we see back further than this?

Which of the following are properties of mechanical waves? check all that apply ⭕️ particles of the medium move back and fourth, but do not move with the wave. ⭕️ the particles of the medium always move parallel to the wave motion. ⭕️ wave motion begins with a disturbance in the medium. ⭕️ waves transport energy from a source outward, away from the source.

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