An apple is dropped from a window 20 m above the ground. How long does it take the apple to reach the ground? What is its final speed?

s = 1/2 at^2

20 = 4.9 t^2
t = 2.02 s

v = at = 9.8 * 2.02 = 19.8m/s

396

19.8m/s

An apple is dropped from a window 20 m above the ground. How long does it take the apple to reach the ground? What is its final speed?

To find the time it takes for the apple to reach the ground, and its final speed, we can use the equations of motion in free fall.

First, we can find the time taken to reach the ground. We can use the equation:

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

Where:
h = height (20 m in this case)
g = acceleration due to gravity (approximately 9.8 m/s^2 on Earth)
t = time

Rearranging the equation, we get:

t = sqrt(2h / g)

Substituting the given values, we have:

t = sqrt(2 * 20 / 9.8)
t ≈ 2.02 seconds

Therefore, it takes approximately 2.02 seconds for the apple to reach the ground.

Now, let's find the final speed of the apple. We can use the equation:

v = g * t

Where:
v = final velocity (speed)
g = acceleration due to gravity (approximately 9.8 m/s^2 on Earth)
t = time (2.02 seconds in this case)

Substituting the values, we have:

v = 9.8 * 2.02
v ≈ 19.8 m/s

Therefore, the apple's final speed is approximately 19.8 m/s when it reaches the ground.