4. If we use plus and minus signs to indicate the directions of velocity and acceleration in one dimension, in which of the following situations does the object speed up?

In the + direction the object speeds up.

Explanation:

Suppose you had a particle moving the x plane, one dimension. It has a positive acceleration if it is moving forward and not backwards from its original place such that it moves in the positive x direction.

answer: d. a cme increases the amount of energy in the solar wind

explanation:

coronal mass ejections, also called cmes, are large clouds of plasma and magnetic field that erupt from the sun. only when the cloud is aimed at earth will the cme hit earth and therefore cause impacts. high-speed solar wind streams come from areas on the sun known as coronal holes.

0.55x745.7j and a calculator