A ball is thrown into the air + missing class

[yumito]

Homework Statement

Gravity = 10m/s/s

The quotes are tables i just couldn't figure out how to make them.

I don't know if velocity is suppose to change but i used 30 for each making the assumption its how hard the initial throw was.

Homework Equations

A ball is thrown into the air

Time (seconds)___Acceleration(m/s/s)___Velocity (m/s)___height (m)
______0_________________________________30___________0
______1
______2
______3
______4
______5
______6

I don't know exactly what the teacher wants because i missed a class but with a couple of assumptions this is what i got

The Attempt at a Solution

A ball is thrown into the air

Time (seconds)___Acceleration(m/s/s)___Velocity (m/s)___height (m)
______0_______________0m/s/s______________30____________0
______1______________ 30m/s/s_____________ 30___________30
______2______________ 20m/s/s______________30___________50
______3______________ 10m/s/s______________30___________60
______4_______________0m/s/s______________30____________60
______5______________-10m/s/s______________30___________50
______6______________-20m/s/s______________30___________30

 

[thrill3rnit3]

Note that "10m/s/s" is not "gravity"; rather, it is the acceleration [ magnitude ] due to gravity.

Now, with that said, which one is constant and which one changes with time: acceleration or velocity?

I'm assuming that you know the definition of these terms. If not then go back to your book/notes.

 

[yumito]

i know its not gravity just trying to speed up the process, and the only thing constant is the seconds.
thats the issue I am having. In the first tabel its suppose to be blank for acceleration i will fix that.
the only things given are for 0 seconds the velocity is 30 and the height is 0.

 

[Norfonz]

Recall from Newton's 2nd law that an object in motion will stay in motion unless some force acts upon it.

The force of gravity will tend to pull the ball back down to Earth's surface. This force is constant! If you draw a free body diagram of the ball at any point during its trajectory, you will see that its weight is the only relevant force (due to gravity). This weight must be constant.

Suppose you give the ball an initial velocity (you have to or it won't go anywhere). It will travel upwards, but its velocity should decrease, shouldn't it? Eventually, it reaches some maximum height and then continues downward, until it hits the ground.

 

[thrill3rnit3]

i know its not gravity just trying to speed up the process, and the only thing constant is the seconds.
thats the issue I am having. In the first tabel its suppose to be blank for acceleration i will fix that.
the only things given are for 0 seconds the velocity is 30 and the height is 0.

If you say that the acceleration of gravity is 10m/s/s, then it is constant. Your 2nd table does not reflect that.

 

[yumito]

just a question is my acceleration correct? or should acceleration just be 10m/s/s for each?

 

[thrill3rnit3]

My post above yours answers that question.

 

[truesearch]

One small point! Newtons second law does not state "an object in motion will stay in motion unless some force acts upon it"

 

[KingBigness]

Think the posts above me explain it well enough. All I can add is it is not m/s/s...this would mean ms/s = m.
Acceleration is m/s^2

 

[truesearch]

m/s/s is not the same as ms/s.
The best way to see this is to write it a m x s^-1 x s^-1 which is m/s^2

 

[PhanthomJay]

Now let's get on with the problem. Use the SUVAT equations of motion for constant acceleration g. The initial velocity is also given. At t = 1, find the velocity and displacement after 1 second has elapsed. Then plug in t = 2 and do the same. Etcetera.