Originally Posted by **jpompey** Thanks for your help it is much appreciated.
I found this way of doing the problem by looking at some websites, and it didn't make very much sense to me because plugging in a negative acceleration renders a negative result. So I think I understand what you're saying, but I'm still a little bit confused because I suppose I never fully understood the equation very well. I see how plugging v = 0 into v = at + V_0 and shifting it around will give t = -V_0 / a but what does the v and the V_0 represent? I'm not very clear on where the v = 0 comes from. Also, in my course I believe we have been usually using V_1 for the initial velocity and V_2 as the next and so on, so could you also please clarify what the V_0 represents? I assume it is the 2.249, but I'm just unclear on where the zero comes from.
Thanks again for your help! |

The "0" subscript on a variable like that means "initial" i.e. its value at t = 0. In this case v(0) = v_0

To be precise: the velocity (a vector quantity) of a body as a function of time is written in two different ways, i.e.

**v** =

**v**(t). If the object is undergoing

*constant* acceleration

**a** (also a vector quantity) and the initial value of its velocity is

**v**_0 then

**v** =

**v**(t) =

**a**t +

**v**_0

Let v be the vertical component of the velocity and v_0 the initial value of the horizontal component of velocity. Then

v = at + v_0

We want to find the time it takes for the body to reach its highest value. The vertical component of the velocity at that time t is zero. The horizontal component of the velocity is constant.

v = 0 = at + v_0

Solve for t

t = -9.8 m/s

My apologies for not recognizing that notation. Its uncommon but not unheard of.