Question

It takes a force of 78.0 N to compress the spring of a toy popgun 0.201 m to "load" a 0.145 kg ball. With what speed will the ball leave the gun?

can anyone help me please

Answer 1

First assume that all of the potential energy of the spring is transformed into kinetic energy of the ball.

Answer 2

yeah but i just dont know how to do it at all im completely lost i just need the answer

Answer 3

Calculate the amount of kinetic energy the ball receives.

Answer 4

cant you give me the answer

Answer 5

please

Answer 6

W = Fs = E

E = .5mv^2 <=> v = sqrt(E/.5m)
v = sqrt(Fs/.5m)
v = sqrt(78.0N*.201m/(.5*.145)) = 14.7053825 m / s

approximately 15m/s

Answer 7

Actually 14.7 m/s is fine.

Answer 8

oh ok let me put it online

Answer 9

no it did not work

Answer 10

i plugged it my homework online

Answer 11

It should be the correct answer. Try changing the rounding.

Answer 12

Oh wait, is this a maths or a physics problem?

Answer 13

physics

Answer 14

in that case i don't see what's wrong with it.

Answer 15

i dont know

Answer 16

can u solve another problem like that one just with different numbers

Answer 17

to see if it works online

Answer 18

this should be extremely simple. see if someone else gets a different result.

Answer 19

no one has tried it only you

Answer 20

hello
help plz

Answer 21

is the gun vertical or horizontal? this matters. Lets assume gun is being fired horizontally
PE_i + KE_i = PE_f + KE_f
PE_i = 1/2 k x^2
KE_i = 0 ball is not moving
PE_f = 0 spring is not being compressed
KE_f = 1/2 m v^2

Answer 22

therefore PE_i = KE_f

Answer 23

plz the answer

Answer 24

v = sqrt(Fx/m)
v = 10.398275719129325085729820157569

answer is wrong if being fired vertically

Answer 25

wait the one you gave me now is wrong ???

Answer 26

Isn't it
v = sqrt(Fx/.5m)

Because
E=.5mv^2 <=> v = sqrt(E/.5m)

?

Answer 27

thank you so much the duke you are right

Answer 28

no
answer depend on how the item is fired

Answer 29

i was trying all night to get it thank you so much duke i truly appreciate it

Answer 30

Zuige
you mistake is the energy is not constant for a spring
the spring energy is 1/2 k x^2 so the work is not simply force times displacement to get energy

Answer 31

oh, of course. sorry for the mistake!

Answer 32

thank u so much to all