Answer:
-45.2m/s
Step-by-step explanation:
If a rock is thrown downward with an initial speed of -6 m/s (negative sign indicates the downward direction), we can calculate its velocity after 4 seconds using the equation for uniformly accelerated motion.
The equation for velocity in uniformly accelerated motion is:
Final Velocity = Initial Velocity + (Acceleration * Time)
In this case, the acceleration due to gravity is acting on the rock, and its value is approximately -9.8 m/s^2 (negative sign indicates the downward acceleration).
Let's calculate the velocity of the rock after 4 seconds:
Initial Velocity = -6 m/s
Acceleration = -9.8 m/s^2
Time = 4 seconds
Final Velocity = -6 m/s + (-9.8 m/s^2 * 4 s)
Final Velocity = -6 m/s - 39.2 m/s
Final Velocity = -45.2 m/s