Iv'e got every value except velocity initial and acceleration. help ?

[pokeefer]

Homework Statement

An accelerating lab cart passes through two photo gate timers 3.0 m apart in 4.2 s. The velocity of the cart at the second timer is 1.2 m/s (4 marks)

a.) What is the cart’s velocity at the first gate?

b.) What is the acceleration?

Homework Equations

v = vi + at
Vaverage = d/t
d = vi(t) + 0.5 at^2
Vf^2 = Vi^2 + 2ad

The Attempt at a Solution

d = 3m
t = 4.2 seconds
vf = 1.2 m/s
vi = ?
a = ?I have tried all of those formulas and they have at least 2 unknowns afterwards.

The question is worth 4 marks so velocity initial can't be 0.

 

[AC130Nav]

posted in error.

 

[pokeefer]

Does that mean this question is invalid?

And if so should I write this as my answer and just hand it in?

 

[AC130Nav]

Does that mean this question is invalid?

And if so should I write this as my answer and just hand it in?

No, it means what I'd posted didn't address your problem, and having submitted I couldn't just delete the whole thing. Sorry for being ambiguous

See if you can find this formula in your book: For uniform acceleration Vavg = (Vf + Vi)/2.

From that and what you've already got, you can get Vi, which let's you get a.

 

[rwisz]

Based on the information given, it seems that you are missing some crucial information. In order to solve for the initial velocity and acceleration, we need to know either the time it takes for the cart to pass through the first gate, or the distance it travels between the two gates. Without this information, it is impossible to accurately determine the initial velocity and acceleration of the cart.

In order to accurately solve this problem, I would suggest going back to the original source of the problem and checking if there is any missing information or if any information was accidentally left out. It is also possible that there may be a typo in the problem itself.

If you are unable to obtain the missing information, you could make an educated guess or estimate for the values based on the given information, but this would not provide an accurate or precise answer. It is important to have all necessary information in order to solve a problem in a scientific manner.