The expression for the frictional force between the sled and the ground is:

where

is the coefficient of friction, m is the mass of the object and

is the gravitational acceleration.
The friction force in our problem is F=80.85 N. The mass of the object is m=15 kg. Re-arranging the formula, we can find the value of k:
Answer:
<h2>3,2 oky na dekh Lena ek bar</h2><h2>2,5</h2>
I normal bubble starts at the speed of 10mph then speeds up +5 each second. so this would be 600 meters. also, it depends on the density of the water and whats inside the water or liquid in the lake. there are many factors that will change this speed.
It’s C I hope it helps you
The height of the rail on top of the press box where the ball was dropped from is 11.025 m.
The given parameters:
- Time of motion of the ball, t = 1.5 s
- Let the height of the rail = h
<h3>Maximum height of fall;</h3>
- The maximum height through which the ball was dropped from is calculated by applying second equation of motion;

Thus, the height of the rail on top of the press box where the ball was dropped from is 11.025 m.
Learn more about height of projectiles here: brainly.com/question/10008919