The gravitational force between earth and the sun is a two-way force. both the planet and the sun attract each other. however, earth revolves around the sun rather than the sun revolving around earth. which statement best explains the orbit of the earth around the sun?

a) the sun is at the center of the solar system.
b) the sun’s mass is much greater than earth’s.
c) earth rotates about its axis, but the sun does not.
d) other planets also try to move the sun around them

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?

The base of a 50-meter tower is at the origin; the base of a 50-meter tree is at (0, 50, 0). the ground is flat and the z-axis points upward. the following parametric equations describe the motion of six projectiles each launched at time t = 0 in seconds. (i) r (t) = (50 + t2)k (ii) r (t) = 2t2 j + 2t2k (iii) r (t) = 50 i + 50 j + (50 − t2)k (iv) r (t) = 2t j + (50 − t2)k (v) r (t) = (50 − 2t) i + 2t j + (50 − t)k (vi) r (t) = t i + t j + tk (a) which projectile is launched from the top of the tower and goes downward? at time t = , the projectile hits the ground at point (x, y, z) = . (b) which projectile hits the top of the tree?

Which of the following is part of the explanation or description of electromagnetic waves? (select all that apply) a. electrically charged molecules in a medium transfer their energy to nearby electrically charged molecules. b. a changing electric field causes a changing magnetic field. c. magnetic molecules in a medium transfer their energy to nearby magnetic molecules. d. a changing magnetic field causes a changing electric field.