Which statement is true?
A. Kepler’s laws apply only to the motion of Earth.
B. Kepler’s laws can be used to predict eclipses.
C. Kepler’s laws are true for a central force that is directly proportional to distance.
D. Kepler’s laws can be deduced from Newton’s laws of motion and gravity.

According to social exchange theory, altruistic behaviors benefit the individual who performs them. t/f

You are given two vectors a⃗ =−3.00ι^ 5.00j^ and b⃗ =5.00ι^ 2.00j^. let the counterclockwise angles be positive.

The space between two 15-in.-long concentric cylinders is filled with glycerin (viscosity = 8.5 × 10-3 lb·s/ft2). the inner cylinder has a radius of 1 in. and the gap width between cylinders is 0.1 in. determine (a) the torque and (b) the power required to rotate the inner cylinder at 180 rev/min. the outer cylinder is fixed. assume the velocity distribution in the gap to be linear.