Not sure this is a physics question (probably biology).
Anyway, the correct answer is A):
"Plasticity helps us to adapt to our environment. It also generally decreases with age".
Plasticity is the ability to adapt to the environment. Since this ability is linked with brain functions, and brain functions worsen with age, then plasticity decreases with age.
It is 6 g/cm3 because density cannot be negative, and it is not speed in which the unit would be m/s.
Answer:
17.6 N
Explanation:
The force exerted by the punter on the football is equal to the rate of change of momentum of the football:
![F=\frac{\Delta p}{\Delta t}](https://tex.z-dn.net/?f=F%3D%5Cfrac%7B%5CDelta%20p%7D%7B%5CDelta%20t%7D)
where
is the change in momentum of the football
is the time elapsed
The change in momentum can be written as
![\Delta p = m(v-u)](https://tex.z-dn.net/?f=%5CDelta%20p%20%3D%20m%28v-u%29)
where
m = 0.55 kg is the mass of the football
u = 0 is the initial velocity (the ball starts from rest)
v = 8.0 m/s is the final velocity
Combining the two equations and substituting the values, we find the force exerted on the ball:
![F=\frac{m(v-u)}{\Delta t}=\frac{(0.55)(8.0-0)}{0.25}=17.6 N](https://tex.z-dn.net/?f=F%3D%5Cfrac%7Bm%28v-u%29%7D%7B%5CDelta%20t%7D%3D%5Cfrac%7B%280.55%29%288.0-0%29%7D%7B0.25%7D%3D17.6%20N)
Explanation:
Below is an attachment containing the solution.