# Angular speed mechanics question

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#1
A model car moves in a circular path of radius 0.8m at an angular speed of
π/2 rads-1. What is its displacement from point P, 6s after passing P?
A zero
B 1.6m
C 0.4πm
D 1.6πm

I am not sure how to do this question or what equations to use and which order to use them in.
0
4 years ago
#2
(Original post by LeCroissant)
A model car moves in a circular path of radius 0.8m at an angular speed of
π/2 rads-1. What is its displacement from point P, 6s after passing P?
A zero
B 1.6m
C 0.4πm
D 1.6πm

I am not sure how to do this question or what equations to use and which order to use them in.
Where is point P? Is it on the circumference of the path?
0
4 years ago
#3
(Original post by LeCroissant)
A model car moves in a circular path of radius 0.8m at an angular speed of
π/2 rads-1. What is its displacement from point P, 6s after passing P?
A zero
B 1.6m
C 0.4πm
D 1.6πm

I am not sure how to do this question or what equations to use and which order to use them in.
I'd start off by calculating how many laps of the track it makes in 6 secs and take it from there
0
#4
(Original post by uberteknik)
Where is point P? Is it on the circumference of the path?
It's on the circumference of the path.
0
4 years ago
#5
(Original post by LeCroissant)
It's on the circumference of the path.
OK. The key words here are angular speed and displacement.

As joinedup said, we need to first work out where the car ends up on the circumference in relation to the starting point P also on that circumference.

You should know that a circle has an internal angle of 360 degrees. Radians are just a way of stating that angle as a multiple of pi around the circumference.

In other words 2 pi radius = to the circumference. i.e. 360 degrees = 2 pi radians.

The question tells us that the car moves around the circumference at pi/2 radius per second.

So, the total angle the car travels through is 6 seconds x pi/2 = 3 pi radians angle from P.

Q. Where does that now place the car on that circumference?
0
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