# Centripetal/Projectile Motion: Proof of Formulas for v^2=mgy

• oridniv
In summary, the conversation is about a physics assignment where the question involves proving the formula v^2=2gR. The person asking for help has tried using a formula but is getting stuck and needs assistance. Another person suggests using conservation of energy to solve the problem.

#### oridniv

from the second question in the link, I've been asked to figure out how to proof some of the formulas. Could someone please help me? I tried using some formulas but I keep getting stuck. If it doesn't show, then could someone please help me proof the formula v^2=mgy

file:///C:/Documents%20and%20Settings/Jenny/Desktop/physics%20assignment2.htm

none of us can access a file on your computer, you're going to have to post the question manually.

A ball on a string is released from rest with the string horizontal and swings through a quarter circle of radius R. At the bottom of the swing the string breaks and the ball is launched horizontally with speed v. The bottom of the swing is a distance 2R above the floor and the ball lands on the floor a distance d away. I'm using v for velocity, R for radius, and g gravity and a for accelaration
We have to prove that v^2=2gR

I used the formula v^2y-v^2oy=2ay(y-yo)
My final answer was -v^2=4gR...something's wrong here because i need help

First: This should be posted in Homework Help.

Second: You can use conservation of energy here to solve it.

## 1. What is centripetal force?

Centripetal force is a force that acts towards the center of a circular path and keeps an object moving in a circular motion.

## 2. How is centripetal force related to projectile motion?

Centripetal force is a type of force that acts on an object in projectile motion, pulling it towards the center of its circular path.

## 3. What is the difference between centripetal and centrifugal force?

Centripetal force is the force that keeps an object moving in a circular path, while centrifugal force is the apparent outward force experienced by an object in circular motion due to its inertia.

## 4. How does centripetal force affect the speed of an object in circular motion?

Centripetal force is directly proportional to the speed of an object in circular motion. This means that as the speed increases, the centripetal force required to maintain the circular motion also increases.

## 5. Can centripetal force act in the absence of a physical force?

No, centripetal force always requires a physical force acting towards the center of a circular path in order to maintain the motion of an object.