Iknow that this is a lot to ask for but i am really struggling with these and my teacher is sub-par, feel free to assist with as many or as few as you want, i really appreciate it.

a cyclist accelerates down a hill from rest at 1.5 m/s2. assuming the acceleration is uniform, how long is required to reach a velocity of 6 m/s?

a cannon ball is thrown straight down from a tower with an initial velocity of 50 m/s. after 2.0 s, what is its final velocity?

what height will be reached by an arrow shot straight up at an initial velocity of 15 m/s? (ignore air resistance.)

a cyclist, riding at a constant speed of 5.0 m/s, sees a flash of lightning. wanting to get home quickly, she accelerates at 1.0 m/s2 for 4.0 s and then rides at a constant speed for 30.0 s. if she then takes a further 12.0 to slow down uniformly to rest, the total distance traveled after seeing the lightning flash is…?

The answers are below

Explanation:

1.-

Data

vo = 0 m/s

t = ?

vf = 6 m/s

a = 1.5 m/s²  

                                t = vf/ a

                                 t = 6 / 1.5

                                t = 4 s

2.-

Data

vo = 50 m/s

t = 2 s

vf = ?

g = 9.81 m/s2

                              vf = vo +´gt

                              vf = 50 + (9.81)(2)

                              vf = 50 + 19.62

                              vf = 69.62 m/s

3.-

Data

height = ?

vo = 15 m/s

g = 9.81 m/s

vf = 0 m/s

                           h = vo² / 2g

                           h = 15² / (2 x 9.81)

                           h = 225 / 19.62

                          h = 11.46 m

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.