According to theory, what best describes the universe before the big bang?
a. a starb. a planetc. a cloud of gas and dustd. a densely packed space

A6,600 kg train car moving at +2.0 m/s bumps into and locks together with one of mass 5,400kg moving at -3.0m/s. what is their final velocity? +0.50 m/s -1.0 m/s +2.5 m/s -0.25 m/s

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

What are the dimensions of the cross section that passes through the points a, f, g, and d?