What is the velocity of an object accelerating at −25.0m/s 2 after 4.0s when it is initially moving at 30.0m/s?

Sure, here's how you can calculate the velocity of the object:

Step 1: Understand the given values. The initial velocity (u) = 30.0 m/s The acceleration (a) = -25.0 m/s² The time (t) = 4.0 s

Step 2: Use the formula for velocity when acceleration and time are known. The formula is: v = u + at

Step 3: Substitute the given values into the formula. v = 30.0 m/s + (-25.0 m/s² * 4.0 s)

Step 4: Solve the equation. v = 30.0 m/s - 100.0 m/s v = -70.0 m/s

So, the velocity of the object after 4.0 seconds is -70.0 m/s. The negative sign indicates that the object is moving in the opposite direction to the initial direction.