# Circular motion problem

• Dec 8th 2011, 06:24 AM
harryjames44
Circular motion problem
A particle in Switzerland travels in a circle of radius 10 km. initially the time taken to complete one circuit is 1 second. After 10 seconds, the particle is travelling so fast that it can complete the same circuit in 0.5 seconds. What is the average tangential acceleration?
(Hint: a particle travelling on a circle of radius R has tangential speed of Rdx/dt, where x is the polar angle in radian. Initially dx/dt= 2π, in this question. And the tangential acceleration is R(d^2 x)/(dt^2 )(Headbang)
• Dec 8th 2011, 06:44 AM
eulcer
Re: Circular motion problem
Does the question say anything about when the particle begins accelerating?
• Dec 8th 2011, 06:46 AM
harryjames44
Re: Circular motion problem
No. that is all they have given.
• Dec 8th 2011, 08:53 PM
Ackbeet
Re: Circular motion problem
Quote:

Originally Posted by harryjames44
A particle in Switzerland travels in a circle of radius 10 km. initially the time taken to complete one circuit is 1 second. After 10 seconds, the particle is travelling so fast that it can complete the same circuit in 0.5 seconds. What is the average tangential acceleration?
(Hint: a particle travelling on a circle of radius R has tangential speed of Rdx/dt, where x is the polar angle in radian. Initially dx/dt= 2π, in this question. And the tangential acceleration is R(d^2 x)/(dt^2 )(Headbang)

What is the initial tangential velocity? What is the final tangential velocity? Can you finish the problem from there?