Question

It takes a force of 80.0 N to compress the spring of a toy popgun 0.200m to "load" a 0.180-kg ball. With what speed will the ball leave the gun? How would I set this problem up? I'm not sure what unit I am aiming for as well. Thank you for your time

Answer 1

Do you know the force devloped on a spring after compressing.Ify yes, state the force .

Answer 2

What is happening here is that you take one of those toy guns and place a ball into it. Then you "load" the gun, that is pull back the spring and it is held there. Once you press the trigger, the spring starts to decompress and pushes the ball out. Look at the attached pic.

The problem told you that you did 80 J of work to compress the spring by .200 m. You asked to find the speed with which the ball is ejected out once you press the trigger of the popgun.

We will be using energy conservation to do the problem. If we assume no energy loss, then the once the spring decompresses, it will lose all of its potential energy (80 J) and transfer it to the ball.

Esstentially, KE=PE
\[\left(\begin{matrix}1 \\ 2\end{matrix}\right)mv ^{2}=80 J\]

Answer 3

@Aditya790 for writing fractions in equation editor, use this syntax

frac{numerator}{denominator}

Answer 4

@shivam_bhalla
Will remember that, thanks. I didn't know how to do it so i used that matrix thing.

Answer 5

No problem, even I learnt it from somebody. So teaching you too :)

Answer 6

Thank you both so much! So then my answer will be in m/s, right?!! :O

Answer 7

Yes ofcourse. SI UNITS :D