# Midway Instantaneous Velocity

## Homework Statement

The position of a particle moving along the x axis is given in centimeters by x = 9.35 + 1.03 t3, where t is in seconds. Calculate the instantaneous velocity when the particle is midway between its positions at t = 2.00 s and t = 3.00 s.

## The Attempt at a Solution

f(2)-f(3)/2
then, solve for t, which will be cubic_root(17.5)
add it to the equation (f(to+h)-f(to))/h as h tends to 0

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kuruman
Homework Helper
Gold Member
Once you have t, you have to put that value in the equation for v(t). What is that equation and what did you get for the value of t?

• fight_club_alum
Once you have t, you have to put that value in the equation for v(t). What is that equation and what did you get for the value of t?
Once you have t, you have to put that value in the equation for v(t). What is that equation and what did you get for the value of t?
8.022

Once you have t, you have to put that value in the equation for v(t). What is that equation and what did you get for the value of t?
I use this equation for the evaluation of tangent, instantaneously, which is in this case is the instantaneous velocity lim h -->0 f(to+h) - f(to) / h

kuruman
Homework Helper
Gold Member
Since you know $x(t)$, It is better to use $$v(t)=\frac{dx(t)}{dt}.$$

On edit:
8.022
I disagree with this value. Can you show how you got it?

Last edited:
• fight_club_alum
Since you know $x(t)$, It is better to use $$v(t)=\frac{dx(t)}{dt}.$$

On edit:

I disagree with this value. Can you show how you got it?
I followed many steps that would be hard to post here

Ray Vickson
Homework Helper
Dearly Missed
I followed many steps that would be hard to post here
How can we possibly help if you will not show what you have done? If you know how to take derivatives, it is simple---hardly needing any work. If you don't know how to take derivatives you will need to a bit more work, but it is still manageable.

Just be careful how you write things: when you write f(t0+h) - f(t0), the standard parsing rules for mathematical expressions interprets this as
$$f(t_0+h) - \frac{f(t_0)}{h},$$
which (I hope) you do not intend. If you mean
$$\frac{f(t_0 +h) - f(t_0)}{h}$$
you need to use parentheses, like this: [f(t0+h)-f(t0)]/h. That forces the subtraction in the numerator to occur before the division.

• fight_club_alum
Chestermiller
Mentor
What is the value of f(3)? What is the value of f(2)? What is the location half-way between these two locations? What is the time corresponding to this half-way location?