Rubber Band

[bhavanam]

A rubber band has mass m=0.30 g and a spring constant k=15 N.m−1 . I stretch it by 5.0 cm (which in this case doubles its length). Assume the rubber band behaves as a Hooke's law spring. Assume that, when you launch the rubber band, all of the stored potential energy is converted into kinetic energy. How fast is it at the launch?

v =_____ m.s−1

[fiction-factory]

You come across as being someone who is not going to benefit from doing this course.
For starters. this mentions Hooke's Law. You must have covered this but if you have forgotten it then wouldn't a good starting point be to look it up, copy down the equation and see whether you have all the info you need to use it.
It mentions PE (that's potential energy if you've never looked at your notes)- what's the formula for that. Then it mentions KE (you work out what that stands for- but the term is in the question)- what is the formula for that - and you'll see a link between KE, m and velocity. You may need a calculator to work out square root.
Make an effort and you might get somewhere