When practicing an oral presentation, you can prepare by writing a draft and practice reading aloud what you are going to say before your oral presentation.
Answer:

Explanation:
The centripetal force acting on the car must be equal to mv²/R, where m is the mass of the car, v its speed and R the radius of the curve. Since the only force acting on the car that is in the direction of the center of the circle is the frictional force, we have by the Newton's Second Law:

But we know that:

And the normal force is given by the sum of the forces in the vertical direction:

Finally, we have:

So, the minimum value for the coefficient of friction is 0.27.
Hello, hello? Hey! Hey, wow, day 4. I knew you could do it.
Uh, hey, listen, I may not be around to send you a message tomorrow. *banging* It's-It's been a bad night here for me. Um, I-I'm kinda glad that I recorded my messages for you *clears throat* uh, when I did.
Uh, hey, do me a favor. *banging* Maybe sometime, uh, you could check inside those suits in the back room? *banging* I'm gonna to try to hold out until someone checks. Maybe it won’t be so bad. *bang bang* Uh, I-I-I-I always wondered what was in all those empty heads back there. *chime plays*.
You know...*deep moan* oh, no - *noises followed by a loud screech and static*
Explanation:
Answer:
548800J
Explanation:
Given parameters:
Mass of roller coaster = 800kg
Height of hill = 70m
Unknown:
Change in potential energy = ?
Solution:
The change in potential energy is the difference between the potential energy at the bottom and at the top.
Potential energy at the bottom is 0J
So;
Change in potential energy = mgh - 0
m is the mass, g is the acceleration, h is the height
Change in potential energy = 800 x 9.8 x 70 = 548800J