Explanation:
Size of the particles of the medium through which, it is passing.
Answer:
(a)

(b)
1120 N
Explanation:
Change in velocity,
is given by subtracting the initial velocity from the final velocity and expressed as 
Where v represent the velocity and subscripts f and i represent final and initial respectively. Since the ball finally comes to rest, its final velocity is zero. Substituting 0 for final velocity and the given figure of 8 m/s for initial velocity then the change in velocity is given by

To find
then we substitute 7 kg for m and -8 m/s for
therefore 
(b)
The impact force, F is given as the product of mass and acceleration. Here, acceleration is given by dividing the change in velocity by time ie

Substituting t with 0.05 s then 
Since F=ma then substituting m with 7 Kg we get that F=7*-160=-1120 N
Therefore, the impact force is equivalent to 1120 N
Answer:
Speed: Distance per time, 400 km/h, and a scalar quantity.
Velocity: Displacement per time, 20 m/s south, and a vector quantity.
Explanation:
Hope this helps! Please mark as brainliest.
Thanks!
Answer:
60km/hr west
Explanation:
When you are dealing with velocity you always name the direction its going in