Question

What is the average velocity during this 11 s interval?

Original question: What is the instantaneous velocity of a freely falling object 11 s after it is released from a position of rest?
Answer I got: -110 m/s

Answer 1

Avg velocity=
total displacement / total time
Total time =11
Total displacement = 1/2*10*11*11

Answer 2

You now have a formula for velocity as a function of time. Use the average velocity formula (or slope formula) to determine the average velocity over the interval [0, 11].

The formula looks like this:\[\frac{ v(x _{2})-(t _{1} )}{ t _{2}-t _{1} }\]

Answer 3

I always appreciate it when you share your work, so that I have something speicifc to which to respond.

Answer 4

I don't understand what numbers im supposed to plug in

Answer 5

@mathmale

Answer 6

what valiue did you use for the acceleration due to gravity?

Answer 7

9.8 m/s^2

Answer 8

OK
instantaneous velocity after 11s = acceleration * time = 9.8 * 11 m/sec

Answer 9

107.8 m/s

Answer 10

or did you use 10? because you have a value of 110?

Answer 11

Oh right 10, I forgot my assignment rounds it up

Answer 12

yes 107.8 is more accurate . We are taking the downerds direction to be positive

Answer 13

110 is you take 10 as acce;eration.

Answer 14

Right.

Answer 15

There's another part to this question if you could help me with it once we are finished with this part.

Answer 16

To calculate the velocity use mathmale's formula

Answer 17

* average velocity

Answer 18

Im not sure what to plug in for all of the parts though

Answer 19

avg velocity = v2 - v2 110 - 0
------ = -------- m / sec
t2 - t1 11 - 0

Answer 20

Okay, so 10 m/s

Answer 21

Let me ask you this; AT WHAT TIME DOES THE INTERVAL BEGIN? Why not represent this with zero (0)? Then, at what time does the interval end?

Next, evalute the velocity at the left end point and again at the right endpoint. Again, the formula for average velocity here would be:\[\frac{ v(x _{2})-v(t _{1} )}{ t _{2}-t _{1} }\]

Answer 22

When you see the words "average of a function," think: "I have to find two different values of that function, based upon the interval endpoints a and b.

In this case your a=0 sec and your b=11 sec. Evaluate velocity v(t) at each of those times.
Then use the formula\[\frac{ v(x _{2})-v(t _{1} )}{ t _{2}-t _{1} }\]

Answer 23

to find the average velocity over the given interval.

Answer 24

You have done this correctly. I hope my summary of the work involved in finding the average value of a function over a time interval helps you understand and remember this material.