F an object goes from 60 mph to 40 mph in 5 seconds what is its acceleration?

To calculate acceleration, use the formula (a = \frac{\Delta v}{\Delta t}), where (\Delta v) is the change in velocity and (\Delta t) is the time taken. Here, the change in velocity ((\Delta v)) is (40 , \text{mph} - 60 , \text{mph} = -20 , \text{mph}). Over 5 seconds, the acceleration is (a = \frac{-20 , \text{mph}}{5 , \text{s}} = -4 , \text{mph/s}). Thus, the object has an acceleration of (-4 , \text{mph/s}), indicating a deceleration.