A marble rolling with speed 20cm/s rolls off the edge of a table that is 80cm high. How far horizontally from the edge of the table edge does the marble strike the floor?

To solve this problem, we can use the kinematic equation for projectile motion:

h = (1/2)gt^2

Where:
h = height of the table (80cm)
g = acceleration due to gravity (980 cm/s^2)
t = time taken for the marble to fall

First, we need to find the time taken for the marble to fall from the table to the floor. We can use the following kinematic equation:

v = gt

Where:
v = final velocity of the marble (20 cm/s)
g = acceleration due to gravity (980 cm/s^2)
t = time taken for the marble to fall

Rearranging the equation to solve for t:

t = v/g
t = 20 cm/s / 980 cm/s^2
t = 0.0204 s

Now that we have the time taken for the marble to fall, we can find the horizontal distance it travels using the following equation:

d = vt

Where:
d = horizontal distance traveled by the marble
v = horizontal velocity of the marble (20 cm/s)
t = time taken for the marble to fall (0.0204 s)

Substitute the values into the equation:

d = 20 cm/s * 0.0204 s
d = 0.408 cm

Therefore, the marble strikes the floor 0.408 cm horizontally from the edge of the table.

8.1cm