A ball is allowed to drop from rest. If the upward direction is positive, then after 2 seconds its velocity will be
A) -19.6 m/s.
B) -9.8 m/s.
C) 9.8 m/s.
D) 19.6 m/s.

Question

Quizplus · Accepted Answer

The velocity of the ball after 2 seconds can be calculated using the equation $v = u + at$, where $u$ is the initial velocity (0 m/s, since it is dropped from rest), $a$ is the acceleration due to gravity (-9.8 m/s$^2$, taking downward as negative), and $t$ is the time (2 seconds). Substituting these values, we get $v = 0 + (-9.8 \times 2) = -19.6$ m/s.

A Ball Is Allowed to Drop from Rest