Step-by-step explanation:
If a cannonball is shot directly upward with a velocity of 160 ft per second. Its height as a function of time is given by :
[tex]h(t)=160t-16t^2[/tex] .......(1)
t is in seconds
(a) Velocity is given by :
[tex]v=\dfrac{dh}{dt}\\\\v=\dfrac{d(160t-16t^2)}{dt}\\\\v=(160-32t)\ ft/s[/tex]
Acceleration is given by :
[tex]a=\dfrac{dv}{dt}\\\\a=\dfrac{d(160-32t)}{dt}\\\\a=-32\ ft/s^2[/tex]
(b) For maximum height put [tex]\dfrac{dh}{dt}=0[/tex]
i.e.
[tex]160-32t=0\\\\t=5\ s[/tex]
Put t = 5 s in equation (1). So,
[tex]h(5)=160t-16t^2\\\\h(5)=160(5)-16(5)^2\\\\h(5)=400\ ft[/tex]
(c) When the ball reaches ground, its height is equal to 0. So,
h(t) = 0
[tex]160t-16t^2=0\\\\t(160-16t)=0\\\\t=0,t=10\ s[/tex]
Hence, this is the required solution.