Question

Help please?
http://oi63.tinypic.com/2ntaeqx.jpg

Answer 1

@ganeshie8

Answer 2

\[\ddot y = g\\
\dot y =gt\\
y=\tfrac12gt^2\\[2ex]
h=\tfrac12gT^2\]

\[\ddot x = 0\\
\dot x = v_{x0}\\
x=v_{x0}t\\[2ex]
d=v_{x0}T\]

Answer 3

Solve for the time of flight \(T\), in terms of the height \(h\).

Use this to find the velocity in the \(x\)-direction \(v_{x0}\), with the equation for the horizontal displacement \(d\).

Answer 4

g=9.81
what should I put for h?

Answer 5

I'm confused by that.

Answer 6

\(h\) is 0.701 m

\(d\) is 3.95 m

Answer 7

What do you get for the time of flight \(T\), in terms of the height?

Answer 8

T=.379

Answer 9

good,

Answer 10

now what is the horizontal velocity \(v_{x0}\)?

Answer 11

Is it the 14.3m/s?

Answer 12

14.3 m/s is the world record horizontal velocity.

Answer 13

vx0 = 10.42 m/s

Answer 14

yep

Answer 15

and the total velocity is
\[v = \sqrt{v_x^2+v_y^2}\]

Where \(v_x=v_{x_0}\), and \(v_y = gT\)

Answer 16

vy=3.72

Answer 17

yeah....

Answer 18

and the vx is still 10.42 right?

Answer 19

yes, \(v_x = v_{x0}\), is constant throughout, as (we are concidering that) there are no forces in the horizontal direction

Answer 20

v=11.06

Answer 21

Yes!

Answer 22

All clear?

Answer 23

Somewhat. So that is the value for the first question asked?

Answer 24

First we found the velocity in the the horizontal direction \(v_{x0}\), assuming that friction on the table was negligible this is equal to the break shot speed.

Then we found the (magnitude of) total velocity at the end of the flight \(v\). This speed that the ball is moving as it hits the ground.

Answer 25

Okay so the 11.06 is for the second one?

Answer 26

And the vx0 is for the first question?

Answer 27

yeah, but wait, i found a typo, that will change the values of the decimal places

h = 0.710 not 0.701 (sorry)

this will effect all your numbers (but not by much)

Answer 28

Vx0=10.37

Answer 29

i'm getting
v_x0 = 10.382 m/s

Answer 30

I might have rounded differently.

Answer 31

v=11.05

Answer 32

Are you getting a number like that?

Answer 33

i'm getting

v = 11.031

Answer 34

close enough

Answer 35

Pretty sure it's just different rounding.

Answer 36

Thanks for the help!