To solve this problem we will apply the linear motion kinematic equations, specifically the concept of acceleration as a function of speed and time, as well as Newton's second law.
PART A) Acceleration can be described as changing the speed in a period of time therefore,
[tex]a = \frac{V}{t}\\a = \frac{11}{8}\\a = 1.375m/s^2[/tex]
Force is the proportional change between mass and acceleration therefore
[tex]F = (73)(1.375)[/tex]
[tex]F= 100.375N[/tex]
PART B) We will apply the same concept given but now we will change the time to 21s therefore:
[tex]a = \frac{V}{t}\\a = \frac{11}{21}\\a = 0.5238[/tex]
Now the force
[tex]F = (73)(0.5238)[/tex]
[tex]F = 38.23N[/tex]
