Fernando tosses a ball upwards with an initial velocity of 12.0 m/s. What is in meters/second the velocity of the ball 4.5 seconds after he threw it?

Subtract g*t from the initial (positive) vertical velocity.

t = 4.5 s, and g is the acceleration of gravity, which you should know the value of.

That will give you a negative number, meaning the velocity will be downwards at that time.

To find the velocity of the ball 4.5 seconds after it was thrown, we can use the equation for motion under constant acceleration. The equation is:

v = u + at

where:
- v is the final velocity
- u is the initial velocity
- a is the acceleration
- t is the time

In this case, the ball is moving upwards against the force of gravity, so its acceleration is equal to the acceleration due to gravity (-9.8 m/s^2). The initial velocity (u) is 12.0 m/s, and the time (t) is 4.5 seconds.

Substituting these values into the equation, we get:

v = 12.0 m/s + (-9.8 m/s^2) * 4.5 s

Calculating the equation:

v = 12.0 m/s + (-44.1 m/s)

v ≈ -32.1 m/s

Therefore, the velocity of the ball 4.5 seconds after it was thrown is approximately -32.1 m/s. Note that the negative sign indicates that the ball is moving downwards.