# A level pure maths modelling question?

no clue how to even start this question
Original post by esha06
no clue how to even start this question
https://share.icloud.com/photos/0d3abRMuUN8OtnnZWoaTBz28Q

The ball will lose energy (restitution) on each bounce and the sequence of bounces will form a geometric sequence. You could almost just write down the values for the first part, though its probably neater to get the formulae.
Original post by mqb2766
The ball will lose energy (restitution) on each bounce and the sequence of bounces will form a geometric sequence. You could almost just write down the values for the first part, though its probably neater to get the formulae.

right so a would be 3 r would be 0.6??
Original post by esha06
right so a would be 3 r would be 0.6??

It tells you its 60% so yes.
Original post by mqb2766
It tells you its 60% so yes.
okay so i’m thinking for part ii it’s probably sum of geometric sequence but how does that make sense if it’s talking about the distance travelled and the sequence refers to how high the ball bounces
Original post by esha06
okay so i’m thinking for part ii it’s probably sum of geometric sequence but how does that make sense if it’s talking about the distance travelled and the sequence refers to how high the ball bounces

What goes up must come down. Distance is in the vertical direction.
(edited 2 months ago)
Original post by mqb2766
What goes up must come down. Distance is in the vertical direction.
okay so i did sum and it wasn’t right so i checked the answers and most of it makes sense but i don’t get how they’re only adding 5 bc when the ball is thrown wouldn’t it go up a bit first increasing the value to more than just 5 going down

https://share.icloud.com/photos/0cd3ApqM-3RnXN64lbpyBP5Ig
(edited 2 months ago)
Original post by esha06
okay so i did sum and it wasn’t right so i checked the answers and most of it makes sense but i don’t get how they’re only adding 5 bc when the ball is thrown wouldn’t it go up a bit first increasing the value to more than just 5 going down
https://share.icloud.com/photos/0cd3ApqM-3RnXN64lbpyBP5Ig

The 5 is because its dropped from a height of 5 at the start. There is no up phase.