Physics questions forces

Hi, please could i have help on this question? I don’t understand why the graph intersects the x-axis? After it rebounds, it goes up at constant acceleration and reaches 0 velocity but why does the graph continue to go up, does it not reach 0 velocity at maximum height?
Here is the question: https://app.gemoo.com/share/image-annotation/632341565084864512?codeId=M07pX5bqdKLJN&origin=imageurlgenerator

Thanks!

Reply 1

mosaurlodon

The downwards direction is positive and the upwards is negative.

So basically the ball is dropped from rest and with downward positive velocity, but then when it hits the ground it rebounds up, which is the sharp rebound spike, and after it bounces on the ground it goes upwards with negative velocity,

Until it reaches max height at 2.1s, where v is 0, and then it goes back down again which is why velocity is positive at then end.

You're correct that velocity is 0 when height is max, but v=0 when the ball bounces, you can imagine a ball bouncing downwards with positive velocity then goes stationary for a moment then comes back up with upwards negative velocity.