Answer:
Part a)

Part b)
Direction = upwards
Explanation:
When ball is dropped from height h = 4.0 m
then the speed of the ball just before it will strike the ground is given as



Now ball will rebound to height h = 2.00 m
so the velocity of ball just after it will rebound is given as



Part a)
Average acceleration is given as



Part B)
As we know that ball rebounds upwards after collision while before collision it is moving downwards
So the direction of the acceleration is vertically upwards
To solve this exercise it is necessary to apply the concepts related to Robert Boyle's law where:

Where,
P = Pressure
V = Volume
T = Temperature
n = amount of substance
R = Ideal gas constant
We start by calculating the volume of inhaled O_2 for it:


Our values are given as
P = 1atm
T=293K 
Using the equation to find n, we have:




Number of molecules would be found through Avogadro number, then


Newton's first law of motion states that. an object on the rest or motion is stay the same unless external force applied on it.
The statement "<span>The maximum intensity increases, and the peak wavelength decreases."</span> is true regarding how black body radiation changes as the temperature of the radiating object increases. Temperature is directly proportional to intensity but inversely proportional to the wavelength.
Using the formula: E = kQ / d² where E is the electric field, Q is the test charge in coulomb, and d is the distance.
E = kQ / d²
k = 9 x 10^9 N-m²/C²
Q = 6.4 x 10^-5 C
d = 2.5 x 10^-2 m
Substituting the given values to the equation, we have:
E = (9 x 10^9)(6.4 x 10^-5) / (2.5 x 10^-2) ²
Electric field at the test charge is 921600000 N/C