Average speed of the runner is the rate at which the runner covers the total distance. Average speed of the runner in the race is given by,
Average speed = 
Where
Total distance = Distance covered by the runner from initial to final position
Total time = time taken by the runner to cover entire distance
Instantaneous speed is the speed of the runner at the particular moment in the given time. Instantaneous speed is given by,
Instantaneous speed = 
x = position of the runner at time t
t = time taken to cover distance x
Hence, Average speed and instantaneous speed are different for a runner running in the race.
I don’t understand can you please explain your question thank u
This instrument is called a spring scale.
Answer:
d = 0 [m]
Explanation:
Displacement is understood as the length and direction that a body travels to move from an initial point to an endpoint.
This displacement is represented with a vector or straight line that indicates the distance of the displacement and its length.
This displacement in an easier way to understand. It is the distance between the start point and the endpoint of the journey. Since the second point is equal to the first point, since Mary returns to the same place, there is no difference between the displacement.
Therefore the displacement is zero.
We now that follow newton rules f=ma so net force equal to mass*acceleration=>f=50*1.5=75 N
