## natasha.aries 3 years ago A student tosses a 2 kg ball into the air 4 meters above his hand. Ignoring air friction, what will be the magnitude of the velocity of the ball when it returns to his hand? A 1 m/s B 2 m/s C 8 m/s D 10 m/s

1. VeritasVosLiberabit

\[v _{f}^{2}=v _{i}^{2}+2a \Delta x\]

2. natasha.aries

but you dont have any velocity

3. VeritasVosLiberabit

hmm but actually I'm getting 8.85 as my answer

4. natasha.aries

would vf be 0?

5. cesckay

mgh=0.5mv^2

6. cesckay

potential energy = kinetic energy

7. natasha.aries

hmm ill try both equations!

8. cesckay

ans= 8.85

9. VeritasVosLiberabit

they give the same answer so I think something is missing.

10. natasha.aries

wait so it doesnt matter which equation?

11. VeritasVosLiberabit

no both give the same result.

12. VeritasVosLiberabit

but Im not sure if the answer is correct since 9 isn't listed.

13. natasha.aries

okay would vf = 0 in @VeritasVosLiberabit

14. VeritasVosLiberabit

vi = 0 you are trying to find vf

15. natasha.aries

the answer is supposed to be 8 so i guess thats close right?

16. natasha.aries

17. VeritasVosLiberabit

hmm but you dont round downward

18. VeritasVosLiberabit

19. natasha.aries

yeah im a little iffy about that but i can try asking my teacher that one tomorrow morning!

20. cesckay

either way the question might be wrong taking g= 9.81... my best answer could be 10 :)

21. natasha.aries

thanks you guys! ill ask my teacher to verify it

22. VeritasVosLiberabit

you're welcome.