# Thread: Circular motion problem

1. ## 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 )

2. ## Re: Circular motion problem

Does the question say anything about when the particle begins accelerating?

3. ## Re: Circular motion problem

No. that is all they have given.

4. ## Re: Circular motion problem

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