You're missing some key information to calculate the acceleration! Here's why and how to solve it:

Understanding Acceleration

Acceleration is the rate of change of velocity. Velocity has both speed and direction. To calculate acceleration, we need:

* Initial Velocity (v_i): The object's starting speed. You've given this as 10 m/s.

* Final Velocity (v_f): The object's ending speed. You've given this as 3 m/s.

* Time (t): How long it took for the object to change its speed.

The Formula

The formula for acceleration is:

* Acceleration (a) = (Final Velocity (v_f) - Initial Velocity (v_i)) / Time (t)

Example

Let's say the object took 5 seconds to change its speed. Here's how we'd calculate the acceleration:

* a = (3 m/s - 10 m/s) / 5 s

* a = (-7 m/s) / 5 s

* a = -1.4 m/s²

Important Notes:

* Negative Acceleration: The negative sign indicates that the object is decelerating (slowing down).

* Units: Acceleration is measured in meters per second squared (m/s²).

Let me know if you have the time it took for the object to change speed, and I can calculate the acceleration for you!