Which equations is not an explicit function of time t, that is, does not involve t as a variable, and is therefore useful when you do not know or do not need the time?

See the explanation below.

Explanation:

The following kinematic equation is very useful as it can determine any of the variables without requiring time.

where:

vf = final velocity [m/s]

vi = initial velocity [m/s]

a = acceleration [m/s^2]

x = distance [m]

Similarly, newton's second law which tells us that the sum of forces is equal to the product of mass by acceleration.

F = m*a

where:

F = total force [N]

m = mass [kg]

a = acceleration [m/s^2]

car stops. he keeps going = he has inertia