Rate of Change: ball is thrown into the air with a velocity of 42 ft/s

[kidgt23]

If a ball is thrown into the air with a velocity of 42 ft/s, its height (in feet) after t seconds is given by y = 42t − 16t². Find the velocity when t = 1.

What I did is that I subbed in when t=1 into the equation to see if I would get when t=1
when I did that i got 26 which is the wrong answer so I do not know what to do.

42(1)-16(1)^2=26

I also have a question on how to do this question

Find a function whose graph is a parabola with vertex (5, −2)
and that passes through the point (3, 2).


What I did hear was I used vertex form to to sub in these values x,y and h,k but then i am lost on what to do.

 

[Deleted member 4993]

If a ball is thrown into the air with a velocity of 42 ft/s, its height (in feet) after t seconds is given by y = 42t − 16t². Find the velocity when t = 1.

Have you been introduced to calculus yet?

What are your thoughts?

Please share your work with us ...even if you know it is wrong.

If you are stuck at the beginning tell us and we'll start with the definitions.

You need to read the rules of this forum. Please read the post titled "Read before Posting" at the following URL:

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[stapel]

Find a function whose graph is a parabola with vertex (5, −2) and that passes through the point (3, 2).

What I did hear was I used vertex form to to sub in these values x,y and h,k but then i am lost on what to do.

Please reply showing what you did, so we can attempt error-checking. Thank you!