Newton's Laws of Motion Question

AI Thread Summary
The discussion revolves around solving a physics problem related to Newton's Laws of Motion, specifically calculating the retarding force needed to stop a race car using a parachute. The user initially attempts to apply the kinematic equation Vsquared=Vosquared + 2ad but struggles with the calculations. After some guidance, they realize the importance of including the negative sign in their calculations, which leads to correcting their approach. The user confirms that simple mistakes can significantly affect the outcome. The thread highlights the common challenges in applying physics concepts accurately.
Lelex
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okay, so I've tried this problem and I keep getting it wrong. I would really appreciate some help in solving it. Here is the question:


The parachute on a race car of weight 8820 N opens at the end of a quarter-mile run when the car is traveling at 35 m/s. What total retarding force must be supplied by the parachute to stop the car in a distance of 1000m?


I know there is probably some really simple equation to solve it but I just can't seem to get it. What i tried was using the equation Vsquared=Vosquared + 2ad

I got 0=35squared + 2a(1000), a=.6125 and then plugged that into F=ma to get F=900(.6125)=551.25

I am I even on the right track with this? Please help!
 
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Looks fine to me.
 
Thanks for looking. I found out the reason I kept getting it wrong was that I forgot the negative sign. It's the silly mistakes that do you in.
 

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