A ball is thrown straight up with an initial velocity of 10 m/s. After 3 seconds its velocity will be
A) -19.4 m/s.
B) -29.4 m/s.
C) 0 m/s.
D) 29.4 m/s.
E) 19.4 m/s.

Question

Quizplus · Accepted Answer

The velocity of the ball after 3 seconds can be found using the equation $v = u + at$, where $v$ is the final velocity, $u$ is the initial velocity (10 m/s upwards), $a$ is the acceleration due to gravity (-9.8 m/s$^2$ downwards), and $t$ is the time (3 seconds). Substituting the values, we get $v = 10 + (-9.8)(3) = 10 - 29.4 = -19.4$ m/s. The negative sign indicates that the velocity is in the opposite direction of the initial throw, meaning the ball is moving downwards after 3 seconds.

A Ball Is Thrown Straight Up with an Initial Velocity