Answer:a) The reaction time can be calculated by dividing the reacting distance by the velocity:
Reaction Time = Reacting Distance / Velocity
Reaction Time = 14 m / 20 m/s
Reaction Time = 0.7 seconds
b) To plot a velocity-time graph, we can assume that the velocity remains constant at 20 m/s until the driver applies the brakes. Then, the velocity decreases linearly to zero over a period of 3 seconds.
The graph would have the following characteristics:
The velocity remains constant at 20 m/s for the initial time.
After 3 seconds, the velocity decreases linearly to zero.
The graph would be a horizontal line at 20 m/s for the first 3 seconds and then a straight downward line reaching zero velocity at the end of the 3-second period.
c) Since the graph shows a linear decrease in velocity, we can estimate the speed at which the driver would hit a wall 3 seconds after first noticing it by looking at the velocity at that time.
From the graph, at 3 seconds, the velocity would be zero, indicating that the car would have come to a complete stop. Therefore, the estimated speed at which the driver would hit the wall is 0 m/s.
Step-by-step explanation: