AQA AS Physics - June 2022 - Paper 2 Question 4.4 - struggling

Hi all, struggling with question 4.4 from AQA AS Physics June 2022 Paper 2. Not sure how to do it and don't understand the marks scheme.

Link to exam paper: https://pmt.physicsandmathstutor.com/download/Physics/A-level/Past-Papers/AQA/AS-Paper-2/QP/June%202022%20QP.PDF

Any assistance would be great.

Her acceleration was 5 ms-2 when between A and B when her chair was accelerating towards the platform. But between C and D she pushes herself back on the rail so the acceleration is 5 ms-2?
Many thanks for your reply.

Yes, along the rail, the acceleration is approximately 5 m/s².

Thanks for your prompt reply but I am confused why acceleration between C and D is equal to acceleration between A and B , can you elaborate on the reason please.

Maybe you want to share your thoughts about what you are confused with.
OR Are you thinking that the acceleration between C and D is NOT equal to the acceleration between A and B? If yes, why?

First of all thanks a million for being patience with my confusion.
My understanding is- between A and B athlete is coming down on rails from rest position and her right foot has touched the platform and after that she has pushed herself up the rail between C and D. So how the acceleration of the downwards motion of the athelete between A and B is equal to the upwards motion on the rail which she achieved by pushing her self upward on the rail by her right leg on the platform between C and D.

Once again, can’t thank you enough for your replies. Much appreciated.

It is always good that you share your thinking so that we know what to explain and leave out the unnecessary to focus on what benefits you the most.

Imagine you throw a ball vertically upward with an initial velocity of 20 m/s.
On the way to the maximum height, what is the acceleration of the ball?
On the way down from the maximum height to your hand, what is the acceleration of the ball?

Now, you throw the same ball vertically upward with an initial velocity of 40 m/s. Again, what is the acceleration the ball on the way up to the maximum height and down from the maximum height to back to your hand?

Note that we are ignoring air resistance or friction.

In all the cases acceleration will be 9.81 ms^-2 while coming down and deceleration while going up.

Indeed, you are right.
To be more precise, I would say, the ball will have the same acceleration (−9.81 m s⁻²) regardless of whether the ball is moving up or coming down or has a different initial speed.

Got it, many thanks