Question

A ball is throw upwards with a intial velocity of 35.0 m/s , what height did the ball reach?

Answer 1

use Vfinal squared = Vinitial squared - 2g*distance

Answer 2

how do i get vf?

Answer 3

ohh wait

Answer 4

well imagine the motion - what's the speed at the highest point ?

Answer 5

actually their was a part a and part b to it

Answer 6

part a asked vwlocity after 3 secs and part b asked velo after 5 secs

Answer 7

part a i got 5.57 and part b i got 14.05

Answer 8

so you throw a ball up at 35m/s and after 3 seconds it has slowed to 5.57 seconds, okay that seems alright
but then 2 seconds after that it is going up even faster again, that can't be right can it ?

Answer 9

its not real life its a problem and when i checked my soultions for a and b i am right

Answer 10

hmm
your answer to part a is right but your answer to part b is wrong in a very important detail

Answer 11

no i checked again i am right

Answer 12

speed at 5 seconds is -14, because it has turned round and is coming back down

Answer 13

yep i got -14.1

Answer 14

so how should i know do c

Answer 15

use the equation i gave you to start with

Answer 16

so should i use 14.1 for vf or 5.57? thats whats confuses me

Answer 17

why would you use either of those values ?

Answer 18

so what should i put in for vf ?

Answer 19

did you read my comment after i posted the equation ?

Answer 20

i dont get it

Answer 21

picture the motion - what would happen in the real world, which this problem is modelling, when the object reaches its highest point ? just tell me in words what you would see

Answer 22

it would then start to drop ?

Answer 23

yes, so it's going up , then after the high point it is coming down

Answer 24

ok so

Answer 25

vf is 0?

Answer 26

correct

Answer 27

problem solved

Answer 28

awesome thanks

Answer 29

you're welcome
remember, 14, -14, big difference : )

Answer 30

i know i put "down" in my answer just didnt tell u that here

Answer 31

ok