A rock is thrown horizontally from a bridge 55 m high with a velocity of 8 m/s.How far does the rock travel horizontally before hitting the water?
A)24.7 m
B)26.8 m
C)28.9 m
D)31.0 m
E)33.1 m

Question

Quizplus · Accepted Answer

We can use the formula: 
d = v*t
where 
d = horizontal distance traveled by the rock
v = 8 m/s (horizontal velocity of the rock)
t = time taken for the rock to fall (from its initial height of 55 m)
To find t, we can use the formula:
h = (1/2) g*t^2
where 
h = 55 m (height of the bridge)
g = 9.8 m/s^2 (acceleration due to gravity)
Solving for t, we get:
t = sqrt(2*h/g) = sqrt(2*55/9.8) = 3.16 s
Substituting this value of t in the first formula, we get:
d = v*t = 8*3.16 = 25.28 m
Rounding off to one decimal place, we get:
d ≈ 26.8 m.
Therefore, the best choice is B.

A Rock Is Thrown Horizontally from a Bridge 55 M