A dog running in the +y-direction at 6.6m/s hears its owner call from behind, and 3.0secs later it's running at the same speed in the opposite direction.
Compute the dog's change in velocity.
Compute its average acceleration.
Change in velocity = -3 - 6.6 = -9.3 m/s
Acceleration = (-9.3 m/s)/3.0s = -3.1 m/s^2
(minus means backwards compared to the +y direction)
To calculate the change in velocity, we need to find the difference between the final velocity and the initial velocity.
Given:
Initial velocity (Vi) = 6.6 m/s
Time (t) = 3.0 seconds
We know that the dog starts running in the +y-direction and then changes direction, so the final velocity will have the opposite sign (-6.6 m/s).
Change in velocity (Δv) = Vf - Vi
= (-6.6 m/s) - (6.6 m/s)
= -6.6 m/s - 6.6 m/s
= -13.2 m/s
Therefore, the dog's change in velocity is -13.2 m/s.
To calculate the average acceleration, we use the formula:
Average acceleration (a) = Change in velocity (Δv) / Time (t)
Substituting the values we calculated:
Average acceleration (a) = (-13.2 m/s) / (3.0 s)
= -4.4 m/s²
Thus, the dog's average acceleration is -4.4 m/s².