Question #5d3e4

Nov 18, 2017

$v = \frac{d}{t}$ is used for Uniform Rectilinear Movements.

Explanation:

Because the formula $v = \frac{d}{t}$ is for an Uniform Rectilinear Movement or for the average velocity in an Uniform Accelerated Movement such as a freefall.

If you use the formula $d = \frac{1}{2} \cdot g \cdot {t}^{2} + {v}_{0} t + {d}_{0}$ you know the exact velocity in a time $t$; in this case, if you substitute $t$ by $10$ $s$ you get the final velocity.

Nov 18, 2017

Free fall is always 9.8t

Explanation:

The difference is due to the d=vt equation being based on average velocity, not instantaneous velocity. For free fall, the initial velocity is zero, and the final velocity is how fast the object is moving just before it hits the ground. You'd find that final velocity using one of the kinematics equations.