A car with a speed of 25m/s weighting 900 kg stops at a distance of 40 m . calculate the force exerted and the work done by the brakes

Asked by pahiroy1221 | 13th Aug, 2015, 08:06: PM

Expert Answer:

begin mathsize 12px style Given colon straight u space equals space 25 space straight m divided by straight s straight v space equals space 0 straight m space equals space 900 space kg straight s space equals space 40 space straight m straight v squared space minus space straight u squared space equals space 2 as 0 space minus space left parenthesis 25 right parenthesis squared equals space 2 space cross times space straight a space cross times 40 straight a space equals space minus fraction numerator 25 squared over denominator 2 space cross times space 40 end fraction space equals space minus space 7.81 space straight m divided by straight s squared Force space equals space straight m space cross times straight a space equals space 900 space cross times space minus space 7.81 straight F space equals space minus 7029 space straight N Negative space sign space indicates space that space straight a space force space exerted space against space the space car space to space stop space it.  Work space done comma space straight W space equals space straight F space cross times space straight s space equals space 7029 space cross times space 40 straight W space equals space 281160 space straight J end style

Answered by Priyanka Kumbhar | 14th Aug, 2015, 08:51: AM