. A car goes along a section of road shaped like the letter S. The speed of the car stays constant. Discuss?

Question

. A car goes along a section of road shaped like the letter S. The speed of the car stays constant. Discuss how the acceleration changes, and make a rough plot.

Answer 1

The answer lies in the definition of Speed".
There's "linear speed" and "Rotational Speed". The framer of the question doesn't say which stays constant, so you can't really answer the question properly without further information.
The linear speed can't remain constant if the speedometer simply stays still, because the component of velocity in any given direction must change if the car is doing an "S" manouvre. On the other hand, if you're doing an "S" manouvre and the speedometer stays the same, then you must be increasing and decreasing the rotational velocity so the acceleration is vectorial and the rotational speed varies as you go round the various parts of the "S".
As you turn, -say - left, into the first curve, your linear velocity decreases, but your rotational velocity increases in that direction. Then it reverses as you perform the next part of the "S" manouvre. After that, you repeat the process into and out of, the final part of the exercise.
Quite difficult, -good question, -hard to answer-, but impossible unless the examiner expands his language to set the question properly.

Answer 2

If you consider the track to be two curved sections joined by a straight section then the car will undergo two periods of constant acceleration in the curved sections and a period of no acceleration on the straight section. If the two curved sections are both of constant radius r and the cars speed is v, then the acceleration is given by -v2/r (v squared over r).

Answer 3

And the velocity changes each time the direction it is facing changes.

I can't draw a diagram on this page.

The acceleration is always in the direction of the force on the car and it is this force which produces the turn.

The force will act between the tyres and the road

Good luck with the diagram.

PS I've just seen the next answer from Always R

ignore it. I used to teach this stuff. There is definitely an acceleration .

Answer 4

there is no way that "the acceleration changes" and yet the speed of the car stays constant.
Well, not where I come from. Ask one of the locals.

Answer 5

draw an "s" being confident you save the x and y axis in innovations placed a speed resultant vector on the automobile at some factors the resultant vector is the hypotenuse of the vectors x and y vectors x and y in simple terms isn't consistent yet will substitute then you are able to communicate acceleration (i desire)

Answer 6

if the speed of the car stays constant, there will be no acceleration.

Answer 7

Do you have the cruise control on? you are controlling the speed of the car ding dong!