# Slingshot flight time

#### ahhhhck

Why do you start counting flight time of a projectile from a slingshot from the point when the projectile leaves the cable and not when it is released? Is it because the elastic potential energy is not converted to kinetic energy until the cable reaches its equilibrium potential?

Thanks.

#### Cawolf

##### Medical Student
5+ Year Member
For simplicity and by convention IMO.

It is as you say that all the energy has not been transferred to the projectile until there is no tension in the spring (slingshot).

So why not start our calculations from the point where we know the energy of the projectile? You can do it however you want, but it is much easier to do as you said.

ahhhhck

7+ Year Member
That'd be like letting initial time (t0) equal to a point in time in which your arm is in mid-throwing-motion (if you were to throw a ball).

The physics at that point is too complex and would not follow simple projectile motion assumptions/principles.

ahhhhck
OP

#### ahhhhck

Thank you! I realised what a dumb question that is after I thought about it some more hahaha

Definitely complicated it unnecessarily