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!

A.h = Vo*t + 0.5g*t^2 = 80

0 + 4.9t^2 = 80

B. V^2 = Vo^2 + 2g*h
V^2 = 0 + 19.6*80 = 1568
V = 39.6 m/s.

C.

A. To find the time needed for the object to hit the ground, we can use the equation of motion: h = 1/2 * g * t^2, where h is the height, g is the acceleration due to gravity (approximately 9.8 m/s^2), and t is the time.

Rearranging the equation, we have:
t = √(2h/g)

Substituting the given values, we have:
t = √(2 * 80 m / 9.8 m/s^2)
t ≈ √(16.33 s^2)
t ≈ 4.04 seconds

So, the time needed to hit the ground is approximately 4.04 seconds.

B. To find the speed of the object when it hits the ground, we can use the equation of motion: v = g * t, where v is the velocity/speed.

Substituting the given values, we have:
v = 9.8 m/s^2 * 4.04 s
v ≈ 39.59 m/s

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

C. The coefficient of friction cannot be directly determined from the given information. The provided information only gives the mass of the object, height, and the depth of the impression it leaves. The coefficient of friction generally depends on the materials, surfaces, and conditions involved.

To determine the coefficient of friction between Earth and the object, additional information or experimentation would be needed, such as measuring the force required to move the object horizontally on Earth's surface.