Question

A force does 600 joules of work on a 2kg object that starts out at rest. How fast is it moving after the work is done? A force does 600 joules of work on a 2kg object that starts out at rest. How fast is it moving after the work is done? @Mathematics

Answer 1

W = (mv^2)/2

So,

600 = (2v^2)/2
600 = v^2
v = 600^(1/2)
v = 24.5 m/s

Answer 2

wow thanks !!!!!!!!!!!!!!!!! I over thought it

Answer 3

2 and 2 cancel out each other

Answer 4

hahah yeah i just saw that :P

Answer 5

can you help me with one more? Do you mind?

Answer 6

Sure. I will try to help with my knowledge. I am still in high school.

Answer 7

Awesome , thanks .I'll write it now :)

Answer 8

4. A child, mass 20kg, jumps off a desk and onto his bed. At the peak of his jump, he is 1.2 meters
above his bed. He lands on two springs in the mattress that both have a spring constant 400 N/m. How
far does he compress the springs

Answer 9

I got 11.606 and the correct answer is 13.17 idk what I did wrong

Answer 10

I am srry, i am not getting the answer that you provided.. :/

Answer 11

:/ for the formula did you get spring potential + gravitational potential = kinetic work?

Answer 12

btw, did you realize that he landed on 2x springs.

Answer 13

Does that matter???????

Answer 14

damn I'm still not getting it

Answer 15

i am srry bro, i am not getting it either. :(

Answer 16

Wanna attempt to help with one more please ? :)

Answer 17

i will try..

Answer 18

hahaha sorry here it is , . A spring with spring constant k=100 N/m is compressed 1.2 meters and shoots a block, m=1kg, off
of a 1.5 meter tall table. How fast is it moving when it hits the ground

Answer 19

It says to use the quadratic formula in this one , but I don't see how it would use it.

Answer 20

Wait never mind it doesn't use the quadratic formulla

Answer 21

ok, a sec..

Answer 22

ok,

1/2 m v^2 = 1/2kx^2

Solve for v

and you get v = 12 m/s for x direction

Answer 23

hmmm my teacher got 13.17

Answer 24

Wait for the last problem I asked what answer did you get? I told you the wrong answer

Answer 25

If you want the velocity in xy direction,

Vy = (2(10)(1.5))^.5 = 5.48 m/s


Vxy = (5.48^2 + 12^2) ^.5 = 13.19 m/s

Answer 26

So the teacher is solving for Vxy.

Answer 27

How did you find the velocity for vy?

Answer 28

ok i used this formula ;

Vf^2 = Vi ^2 + 2ax

Answer 29

Ohh I remeber that

Answer 30

I got 0.77 m for the last problem..

Answer 31

i might be wrong... =/

Answer 32

what is the answer for the last one?

Answer 33

ohhh it was 1.05, but yeah I got that also while taking the two springs in account . But when I used one spring I got 1.08. He uses the quadratic formula for that one but I don't know how

Answer 34

hmm.. ok i am glad you got the answer.

Answer 35

I'm off by .2 which worries me :P Cause I didn't even use the quadratic formula

Answer 36

But I can't really see how you're getting Vy using that formula ?

Answer 37

lol it's totally fine. Ok

So you have the height(1.5), the initial velocity is (0), acceleration is gravity (10), and you just solve for the final velocity then, you will get the velocity for y direction.

Answer 38

But why to the power of .5?

Answer 39

oh well i can't type square root here. It basically means square root. sqrt(x) = x^(1/2) = x^.5

Answer 40

ohh I thought so . thanks :) And for finding Vxy did you use the same formula ? and how?

Answer 41

nope i used Pythagorean theorem.

Answer 42

Ohhhhhhhhhh that totally makes sense now man. Thanks so much. You've been a tremendous help. Sorry for bugging you

Answer 43

It's my pleasure. good luck.. ^.^