A stone is dropped from a 100m bridge. How long does it take the rock to reach the ground?

Vertical Going down postive

d=100m
a=+9.8m/s2
V1=0

Use the formula
d=v1t=1/2 a t*2
100= 1/2 (9,8) t*2
100=4.9t*2
Divide 4.9 from both sides
20.4=t*2
square root 20.4
t=4.51s

To calculate the time it takes for the stone to reach the ground, we can use the equation for the motion of a falling object under gravity. The equation is:

h = (1/2) * g * t^2

Where:
h = height (100m in this case)
g = acceleration due to gravity (approximately 9.8 m/s^2)
t = time

Rearranging the equation to solve for time:

t^2 = (2h) / g

t = sqrt( (2h) / g )

Now, we can substitute the values into the equation:

t = sqrt( (2 * 100) / 9.8 )
t = sqrt( 20.408 )

Using a calculator or manually calculating the square root, we find that t is approximately 4.5 seconds.

Therefore, it takes approximately 4.5 seconds for the stone to reach the ground when dropped from a 100m bridge.