Which one of these formulas are used to find T (time)?

Below

Explanation:

You can actually use ALL EXCEPT THE LAST ONE of these equations to find t, time! It really just depends on what values you are given in the question! Basically what you want to do is plug in everything you have, and solve for t! For example :

Let's say that a car begins from rest and accelerates at 4.2 m/s^2 [ forward ] until it reaches a speed of 62 m/s.

     vi = 0m/s, vf = 62 m/s, a = 4.2 m/s^2

We can use the 3rd equation to solve :

     vf = vi + at

     62 = 0 + 4.2(t)

     62 = 4.2t

     14.76 = t

     15 seconds = t

Hope this helps!

anchor = archer //

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s