Consider a particle moving along the x-axis whose velocity as a function of time is dx_ _ gt dt yi+ g 2 t 2 where g is a constant.

(a) does the particle’s speed ever exceed the speed of light?

(b) calculate the components of the particle’s four-velocity.

(c) express x and t as a function of the proper time along the trajectory.

(d) what are the components of the four-force and the three-force acting on the particle?

Why is rain likely when warm, moisture-laden air meets cold air? a) the lighter warm air will rise and cool down, causing condensation and rain. b) the cold air moves faster and pushes the warm air away, causing condensation and rain. c) the moisture in the warm air condenses on contact with the cold air, causing rain to fall. d) the cold air mixes with the warm air, reducing its temperature causing moisture to condense.