Mary and Debra stand on a snow-covered roof.They both throw snowballs with the same initial speed,but in different directions.Mary throws her snowball downward,at 30° below the horizontal; Debra throws her snowball upward,at 30° above the horizontal.Which of the following statements are true about just as the snowballs reach the ground below? Neglect the effects of air.(There could be more than one correct choice.)
A)Debra's snowball will have a higher speed than Mary's snowball.
B)Mary's snowball will have a higher speed than Debra's snowball.
C)Both snowballs will hit the ground with the same speed.
D)Both snowballs hit the ground at the same time.
E)Mary's snowball reaches the ground before Debra's snowball.

Question

Quizplus · Accepted Answer

Both snowballs will have the same speed upon hitting the ground due to conservation of energy, assuming they start from the same height. However, Mary's snowball, thrown downward, will reach the ground before Debra's, which is thrown upward and thus has a longer trajectory.

Mary and Debra Stand on a Snow-Covered Roof