# Calculus

posted by .

1.if a ball is thrown into the air with a velocity of 35ft/s, it's height in feet after t seconds is given by y=35t-10t^2. Find the averag velocity for the time period beginning when t=4 and lasting 0.05s.
2.if a ball is thrown into the air with a velocity of 30ft/s, it's height in feet after t seconds is given by y=30t-20t^2. Find the instantaneous velocity when t=3

• Calculus -

Last time I was on this earth, gravity would cause an equation of the type
y = -16t^2 .....
So assuming you have a typo and it should have been
y = 35t - 16t^2
Second problem:
the ball would not be in the air for 4 seconds,
so your whole first question is actually just gibberish.
Once you fix it, find y when t = 4
find y when t = 4.05
evaluate: ( y(4.05) - y(4) )/.05

2. same thing here,
after 3 seconds the ball has reached the ground, and no longer has any velocity

if we ignore reality,
dy/dt = 30 - 40t
when t = 3
dy/dt = 30 - 120 = -90 ft/s

1.
when t=4, y = 35(4) - 16(16) = -20

• Calculus -

There is no error in the problem.

• Calculus -

I see the typo as specifying feet. In metric units, g=9.8, or roughly 10, so Jacke, redo the calculations, with g=10 and get the correct answer.

• Calculus -

Is it ok if I get a negative answer???

• Calculus -

OK thanks I got it

## Similar Questions

1. ### Calculas

If a ball is thrown in the air with a velocity 44 ft/s, its height in feet t seconds later is given by y = 44t - 16t2. (a) Find the average velocity for the time period beginning when t = 2 and lasting 0.5 second. ft/s (b) Find the …
2. ### Calc

If a ball is thrown into the air with a velocity of 30m/s, its height in metres after t seconds is given by y=30t-4.9t^2 Fing the average velocity for the time period beginning when t=2 and lasting 1second. I did V(1)=lim h->0 [[30(1+h)-4.9(1+h)^2]-[30(1)-4.9(1)^2]]/h …
3. ### Math

If a ball is throw into the air with a velocity of 40ft/s its height in feet t seconds later is given by: y=40t-16t^2. Find the average velocity for the time period beginning when t=2 and lasting 0.5 seconds.
4. ### math

If a ball is thrown straight up into the air with an initial velocity of 95 ft/s, it height in feet after t second is given by y=95t–16t2. Find the average velocity for the time period begining when t=1 and lasting (i) 01 seconds: …
5. ### Math

If a ball is thrown straight up into the air with an initial velocity of 95 ft/s, it height in feet after t second is given by y=95tâ€“16t2. Find the average velocity for the time period beginning when t=2 and lasting i) 0.1 seconds …
6. ### Calculus

If a ball is thrown in the air with a velocity 44 ft/s, its height in feet t seconds later is given by y = 44t - 16t2. (Round your answers to one decimal place.) (a) Find the average velocity for the time period beginning when t = …
7. ### calculus

If a ball is thrown straight up into the air with an initial velocity of 70 ft/s, it height in feet after t second is given by y = 70 t - 16 t^2. Find the average velocity for the time period begining when t = 1 and lasting (i) 0.1 …
8. ### Calculus

If a ball is thrown straight up into the air with an initial velocity of 95 ft/s, its height in feet after t seconds is given by f(t)=95t−16t^2 Find the average velocity for the time period beginning when t=1 and lasting (i) …
9. ### Calculus

If a ball is thrown straight up into the air with an initial velocity of 95 ft/s, its height in feet after t seconds is given by f(t)=95t−16t^2 Find the average velocity for the time period beginning when t=1 and lasting (i) …
10. ### Calculus

If a ball is thrown into the air with a velocity of 40 ft/s, its height in feet t seconds later is given by y = 40t − 16t^2. Find the average velocity for the time period beginning when t = 2 and lasting for each of the following. …

More Similar Questions