Which of the following is about as cheap as coal for base-load ...

[rmenurse]

Which of the following is about as cheap as coal for base-load electric power today?
 
  A) photovoltaic cells
  B) solar-thermal generation of electricity
  C) wind turbines
  D) All of the above.
  E) None of the above.

Question 2

A foul ball is hit straight up into the air with a speed of 30 m/s, and air resistance is negligible.
  (a) Calculate the time required for the ball to rise to its maximum height.
 
  (b) Calculate the maximum height reached by the ball above the point where it hit the bat.
  (c) Determine the times at which the ball passes a point 25 m above the point where it was hit by the bat.
  (d) Explain why there are two answers to part (c).

[krakiolit]

Answer to Question 1

C

Answer to Question 2

(a) 3.1 s (b) 46 m (c) 1.0 s and 5.1 s
(d) One value for the ball traveling upward; one value for the ball traveling downward.

[rmenurse]

Gracias!

[okolip]

Excellent