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#1 2007-10-17 03:58:15

hannah_106
Member
Registered: 2007-10-17
Posts: 3

kinematics

rocket powered sledge accelerates at 35ms-2 and takes 1.6s to pass through a 60m section of a test track. Find the speed at which it entered the section what was its speed when it left?

I think this is the equation to use x=ut + 1/2at2 and than use a=v-u/t to get v ?

a= 35m/s
t= 1.6s
u=?
v=?
x= 60m




please show your working

thanks

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#2 2007-10-17 04:37:23

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: kinematics

That’s right. The suggestion you make is the method to use to solve the problem. So use it.

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#3 2007-10-17 04:59:13

hannah_106
Member
Registered: 2007-10-17
Posts: 3

Re: kinematics

JaneFairfax wrote:

That’s right. The suggestion you make is the method to use to solve the problem. So use it.

thats what I am having problems with, I rearranged it to give 'u' but it gave the wrong answer as the right answer is 9.5. but i dont know how to get this.

can someone show a worked example?

thanks

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#4 2007-10-17 05:11:36

bossk171
Member
Registered: 2007-07-16
Posts: 305

Re: kinematics

It might help if you posted your work to date (even if it's wrong) then we can say, "there, that's where the mistake was made!"

Also, are you absolutely sure the answer is wrong? If you got the answer from the back of the book, it might be wrong, some books have an absurdly high error rate.


There are 10 types of people in the world, those who understand binary, those who don't, and those who can use induction.

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#5 2007-10-17 05:41:16

Daniel123
Member
Registered: 2007-05-23
Posts: 663

Re: kinematics

You should have:

Then, using v = u + at:

Last edited by Daniel123 (2007-10-17 05:46:13)

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