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A car weighing 1000 kg is travelling at the speed of 15ms^(-1). It decelerated due to brakes applied and stops after covering a distance of 25 m. Find the force exerted by the brakes and the work done by the brakes. |
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Answer» `s=25m` `v^(2)-u^(2)=2as` `therefore 0-(15)^(2)=2axx25` `therefore -225=50alpha` `therefore a=-(225)/(50)=-4.5ms^(-2)` Negative acceleration means DECELERATION. `therefore` Deceleration `=4.5ms^(-2)` Decelerating FORCE `F=ma` `=1000kgxx4.5ms^(-2)` `=4500 N` WORK done by the brakes, `W=Fs` `=4500kgxx25m` `=112500J` |
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