Is My Calculation of Force and Acceleration Correct?

[goonking]

http://imgur.com/DZPb7oa

How do I even start that? I replace t with 7.6

so F(7.6) = 13.78 which is the force, correct?

F= ma

13.78 = 6 kg x a

a = 2.3 m/s2

is this correct so far? am i on the right route?

 

[PeroK]

You need to use the Homework Template.

Have you learned the integral calculus?

 

[goonking]

You need to use the Homework Template.

Have you learned the integral calculus?

very briefly. is it required to do this problem?

isn't integral calculus just +1 to the exponent and divide the whole term by the new exponent??

hint says the integral of acceleration is velocity but the only equation they give us is for force.

 

[NascentOxygen]

The force is not constant, it is continually changing with time.

Using calculus, what is the general expression for velocity in terms of acceleration?

 

[goonking]

The force is not constant, it is continually changing with time.

Using calculus, what is the general expression for velocity in terms of acceleration?

integral i believe? since derivative of velocity gives you acceleration.

 

[NascentOxygen]

If you click on the capital sigma $(\Sigma)$ in the toolbar of the text entry box below you will see some useful symbols appear; among them is an integral sign.

 

[goonking]

integral i believe?

If you click on the capital sigma $(\Sigma)$ in the toolbar of the text entry box below you will see some useful symbols appear; among them is an integral sign.

so do I find the integral of F(t) to give me velocity?

 

[NascentOxygen]

so do I find the integral of F(t) to give me velocity?

That's close, but you have to be exact if you hope to get the right answer.

I hoped that by my pointing out the integral sign, you might be encouraged to use it.

 

[goonking]

That's close, but you have to be exact if you hope to get the right answer.

I hoped that by my pointing out the integral sign, you might be encouraged to use it.

F(t) is the only equation there I can integrate, how can I get a more exact answer?

 

[NascentOxygen]

You know that the time integral of force doesn't have units of metres/second. So how can you convert your force into something that can be integrated to give velocity?

 

[goonking]

You know that the time integral of force doesn't have units of metres/second. So how can you convert your force into something that can be integrated to give velocity?

convert force to acceleration? F = ma?

 

[NascentOxygen]

convert force to acceleration? F = ma?

Right. And you can see that the "conversion" involves a proportionality constant.

 

[goonking]

Right. And you can see that the "conversion" involves a proportionality constant.

I'm getting the answer to be 17.45 meters/sec.

is that what you are getting too?

 

[PeroK]

I'm getting the answer to be 17.45 meters/sec.

is that what you are getting too?

How did you get that answer?

 

[goonking]

How did you get that answer?

http://imgur.com/i1Xyq2G

the answer is wrong though. DAMN

 

[NascentOxygen]

It's wrong because you didn't integrate.

First step is to convert F(t) to a(t), acceleration as a function of time. Then integrate this a(t) to arrive at v(t).

 

[goonking]

It's wrong because you didn't integrate.

First step is to convert F(t) to a(t), acceleration as a function of time. Then integrate this a(t) to arrive at v(t).

so to convert F(t) to a(t), do you just divide F(t) by the mass 6kg? since F=ma

 

[NascentOxygen]

so to convert F(t) to a(t), do you just divide F(t) by the mass 6kg? since F=ma

Yes, that's it!

 

[goonking]

Yes, that's it!

yes! the answer is 11.63 m/s.
thank you! finally I can move on

 

[NascentOxygen]

We would appreciate it if you'd type in your working as text, rather than attach a pic. That way we can quote a line that needs attention, as well as it being more legible (usually), and for those using mobile devices the download is faster and far less costly. Please bear that in mind for future postings.

 

[goonking]

We would appreciate it if you'd type in your working as text, rather than attach a pic. That way we can quote a line that needs attention, as well as it being more legible (usually), and for those using mobile devices the download is faster and far less costly. Please bear that in mind for future postings.

I'm not too familiar with posting my work as text. Do I need a program to do that?

 

[NascentOxygen]

I'm not too familiar with posting my work as text. Do I need a program to do that?

That means you type it on your keyboard as F=ma and v(t)=∫a(t).dt

For more complicated mathematical expressions, you can start to learn Latex.