Question 7

A girl on a bridge 4 m above a stream throws a heavy rock into the air with a speed of 20 m/s, at an angle with respect to the horizontal. For which of the following values of is the speed of the rock the greatest when it hits the water? (Neglect air resistance.)

• A.    +90 degrees (straight up)
• B.    -90 degrees (straight down)
• C.    0 degrees (horizontal)
• D.    45 degrees (obliquely down)
• E.    The angle does not matter

Formula Sheet

Question 6

Question 8

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