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
The last one, the soil will become weak & unable to support plant growth
Answer:
Evaporation is the physical change in which a substance converts from its <u>liquid</u> state to its <u>gaseous</u> state. Condensation is the physical change in which a substance converts from its <u>gaseous</u> state to its <u>liquid</u> state.
Explanation:
Evaporation and condensation are opposite processes to each other. Evaporation changes a liquid to a gas and condensation is the reverse.
Look at the third one i think its the answer