Question

A rock dropped off a bridge takes 5 seconds to hit the water. Approximately what was the rock's velocity just before impact?

A) 5 m/s

B) 2 m/s

C) 50 m/s

D) 125 m/s

Answer 1

The rock's velocity just before impact after falling for 5 seconds is approximately 49 m/s, calculated using the free fall formula v = gt. Since none of the provided choices match this exact value, the closest option is C) 50 m/s.

Step-by-step explanation:

The velocity of a rock just before impact after being dropped off a bridge can be calculated using the formula for the velocity of an object in free fall: v = gt, where g is the acceleration due to gravity (approximately 9.8 m/s2), and t is the time the object has been falling. In this case, t = 5 seconds.

Using the formula:

• v = gt
• v = 9.8 m/s2 × 5 s
• v = 49 m/s (approximately)

So, the velocity of the rock just before impact is approximately 49 m/s. None of the answer choices match this value exactly, but choice C) 50 m/s is the closest approximation.