To determine acceleration from the slope of the speed-time curve, you need to take the derivative of the speed-time curve. The derivative of the speed-time curve is the acceleration-time curve.
The slope of the speed-time curve represents the rate at which the object's speed is changing with respect to time. Specifically, the slope of the speed-time curve at any given point is equal to the instantaneous acceleration at that point in time.
If the slope of the speed-time curve is positive, the acceleration is positive, meaning the object is increasing its velocity, while if the slope is negative, the acceleration is negative, which indicates that the object is slowing down.
In mathematical terms, the equation that relates acceleration, velocity, and time is:
a = dv/dt
Where:
a = acceleration
v = velocity
t = time
Therefore, if you know the velocity-time curve, you can easily calculate the acceleration-time curve by taking the derivative of the velocity-time curve using calculus.