Superman's acceleration is constant at -3 m/s^2, signifying a steady deceleration. The velocity change from 15 m/s to -15 m/s in 10 seconds yields a uniform negative acceleration, depicted by a horizontal line at -3 m/s^2 on a velocity-time graph.
Acceleration (a) is calculated as the change in velocity (Δv) divided by the change in time (Δt):
a = Δv / Δt
In the case of Superman's velocity over time, his velocity changes from 15 m/s to -15 m/s in 10 seconds. This gives us a change in velocity (Δv) of -30 m/s:
Δv = v_f - v_i = -15 - 15 = -30 m/s
The change in time (Δt) is 10 seconds:
Δt = t_f - t_i = 10 - 0 = 10 s
Now, we can calculate Superman's acceleration (a) using the formula:
a = Δv / Δt = -30 / 10 = -3 m/s^2
This means that Superman's acceleration is constant and negative, indicating that he is slowing down at a constant rate. The graph representing his acceleration over time would be a horizontal line at -3 m/s^2.
Complete question:
Superman runs until reaching his flight takeoff speed of 15 m/s . A graph of his velocity over time is shown below, where rightward is the positive velocity direction. Velocity ( m/s ) Which graph shows his acceleration over time?