An object with a mass of 100kg is dropped from an 80 meter high building and leaves an impression in the ground of 15cm.

A.What is the time needed to hit the ground?
B. What is the speed of the object when it hits the ground?
C. What is the coefficient of the friction between Earth and the object?

Please show all work!

See previous post: Fri,11-1-13,1:00 AM.

A. To calculate the time needed to hit the ground, we can use the equation of motion for free fall:

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

Where:
d = distance fallen (80 meters)
g = acceleration due to gravity (approximately 9.8 m/s^2)
t = time

Rearranging the equation, we have:

t^2 = (2 * d) / g

Plugging in the values:

t^2 = (2 * 80) / 9.8
t^2 = 16.33

To find t, we take the square root of both sides:

t ≈ √16.33
t ≈ 4.04 seconds

Therefore, it would take approximately 4.04 seconds for the object to hit the ground.

B. To calculate the speed of the object when it hits the ground, we can use the equation of motion for free fall:

v = g * t

Where:
v = final velocity (speed)
g = acceleration due to gravity (approximately 9.8 m/s^2)
t = time (4.04 seconds)

Plugging in the values:

v = 9.8 * 4.04
v ≈ 39.59 m/s

Therefore, the speed of the object when it hits the ground is approximately 39.59 m/s.

C. The coefficient of friction cannot be determined solely from the information given. It depends on various factors such as the surface the object is in contact with and the materials involved. To determine the coefficient of friction, additional information such as the force exerted by the object and the type of contact surface is required. Without this information, the coefficient of friction cannot be calculated.