Not good at physics problems, need !

Next time, please post in the physics section. It is not exactly a math problem because it requires knowledge of kinematics equations, assumptions and constants.

Given:

A rocket fired (assumed vertically upwards) at an initial velocity of +123 ft./s (positive upwards) against acceleration due to gravity of (assumed -32.2 ft/s^2) at an initial height of +4 feet above the ground. Need to find the time it takes before rocket reaches ground (assuming air resistance negligible) due to free fall.

Kinematics equations:

Using given numerical information

u=inivitial velocity=+123 ft/s

g=acceleration due to gravity= -32.2 ft/s^2

s0=initial location, height=+4 ft

s1=final local, height = 0 ft (ground)

We make use of the kinematics equation

s1=s0+u*t+at^2(1)

where a=acceleration = g = -32.2 ft/s^2

Subsitute values in (1)

0=4+123*t-32.2t^2

and solve for t using the quadratic formula (knowing that t>0)

t=[-123 ± sqrt(123^2-4*(-32.2)*4)]/(2*-32.2) =>

t = -0.03225 sec. or t=3.852 sec.

Reject negative root, so the rocket will hit the ground 3.852 seconds since airborne.

Note: since #61 and #62 are pale in colour, it will be assumed that you can handle those two, or they will be the subject of other questions. Thank you.

i dont know

step-by-step explanation: