Question

The speed in meters/second of a ball dropped from height h meters is given by the function v = √20h. Its kinetic energy in joules (J) is given by the function T = 2v^2. What is the ball's kinetic energy if it is dropped from a height of 3 meters?
(Hint: First find speed and then find kinetic energy.)

Answer 1

120 joules

60 joules

20 joules

80 joules

Answer 2

well you can find the speed v
by using the height 3 meters
first

then you can find T by using that result

Answer 3

sqrt(20)h?

Answer 4

I don't know.
I can't read your v.

Answer 5

sqrt(20)(3)

Answer 6

They dont give you V

Answer 7

\[v=\sqrt{20 h} \text{ or } v=\sqrt{20} h\]
yes they do
I just can't tell what you mean

Answer 8

so 6sqrt(5)+ 6sqrt(5)?

Answer 9

nvm

Answer 10

what is v?

Answer 11

is it the first one i mentioned or the second one ?

Answer 12

6qrt(5)

Answer 13

v is the first one

Answer 14

ok \[v=\sqrt{20 h} \\ \]
so you replaced h with 3 since h=3 meters
\[v=\sqrt{20 \cdot 3}\]
ok and we know 20*3 is 60
so
\[v=\sqrt{60}\]
now you can finally find T by pluggin this in to the T function you were given

Answer 15

ok

Answer 16

\[2\sqrt{60}^2\]

Answer 17

right and that is pretty easy to calculate
because the square thing will cancel the square root thing

Answer 18

yea

Answer 19

thx