Motion problems: deceleration equation and velocity perpendicularity

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zacky_D
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Doubts regarding 3 question form motion of a particle! :)

Homework Statement



Doubts related to 3 problems..I have uploaded the question up in the attachment.

Homework Equations





The Attempt at a Solution


for question one,the body doesn't come to rest,s is the total dist at any instant after it started decelerating with retardation β.If it comes to rest,answer is 2s/v,and such a problem is there in irodovs general problems book..but how to get a general equation,for any instant after it starts decelrating with b?

question 3:i attempted using vectors and taking dot product equal to zero,but didnt arrive anywher,so someone please help! :)
 

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Someone please Reply! :(
 


zacky_D said:

Homework Statement



Doubts related to 3 problems..I have uploaded the question up in the attachment.

Homework Equations



The Attempt at a Solution


for question one,the body doesn't come to rest,s is the total dist at any instant after it started decelerating with retardation β.If it comes to rest,answer is 2s/v,and such a problem is there in irodovs general problems book..but how to get a general equation,for any instant after it starts decelerating with b?

question 3:i attempted using vectors and taking dot product equal to zero,but didn't arrive anywhere,so someone please help! :)
Hello zacky_D. Welcome to PF !
zacky_D said:
Someone please Reply! :(
Patience, Please !

While you're waiting for a reply, please read the rules for this Forum. You will see there that you should wait 24 hours before "bumping" your thread.


For Problem #1: You are correct in regards to you conclusion that the car nedds to come to rest in order for a solution to be possible.

As regards the somewhat similar Irodov problem, I believe that the Irodov problem assumes that the magnitude of the acceleration, α, is equal to the magnitude of the deceleration, β. In that case, the total time is s/vaverage = 2s/vmax. You generally would want to express this answer in terms of s and α, not s and vmax .


As for your attempt at a solution to #3: You will need to give more details as to what you tried, before we can be of much help.