contestada

3. Daniel stands on a bridge over a river. He drops a coin and notes that the coin takes 3 s to reach the river below.

He must be standing

above the river.

A 10 m

B. 15 m

C. 30 m

D. 45 m

Respuesta :

tochjosh

Answer:

45 m

Explanation:

Initial velocity of the coin = 0 m/s  (since he dropped it from his hands)

time spent in falling - 3 sec

distance s = ?

using

s = ut + [tex]\frac{1}{2}[/tex]g[tex]t^{2}[/tex]

where

s is the distance the stone fell

u is the initial velocity

t is the time spent falling

g is acceleration due to gravity = 10 m/s^2 (positive downwards)

substituting values, we have

s = (0 x 3) +  [tex]\frac{1}{2}[/tex](10 x [tex]3^{2}[/tex])

s = 45 m