# Rounding a Curve

## Homework Statement

A car rounds a level curve of radius 100 meters at a constant speed of 30 m/s.
What is the magnitude of the acceleration of the car?

C = 2piR

## The Attempt at a Solution

I calculated the circumference as 628m. Besides that, I'm ignorant of the procedure to solve this.

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kuruman
Homework Helper
Gold Member
1. A car rounds a level curve of radius 100 meters at a constant speed of 30 m/s.
What is the magnitude of the acceleration of the car?

C = 2piR[/B]

## The Attempt at a Solution

I calculated the radius as 628m. Besides that, I'm ignorant of the procedure to solve this.[/B]
What have you learned about cars going around curves? Do they accelerate?
The radius is given as 100 m. You cannot claim that it is 628 m. Please pay attention to what you are doing.

I intended to type "circumference" instead of "radius." This is the first time I encountered this type of question. My initial estimation was the acceleration would be zero if the speed is constant.

kuruman
Homework Helper
Gold Member
I intended to type "circumference" instead of "radius." This is the first time I encountered this type of question. My initial estimation was the acceleration would be zero if the velocity is constant.
The speed is constant but not the velocity. Velocity has direction which in this case is changing. Speed has no direction. The speedometer in a car indicates the speed but it does not indicate in which direction the car is moving; that's why it's called a "speedometer".

Does the question make more sense now? This problem must be related to a section in your textbook, notes or material covered in class. What is the acceleration when something goes around in a circle?

Yes, I understand the distinction now because acceleration is the change in velocity rather than speed. Unfortunately, we never reviewed this subject in class. Gravity is vertically holding the car to the earth. That seems irrelevant if it's horizontally turning a corner.

kuruman