Another phys ques.regarding force

Question

a vehicle of mass 1800 kg moves with uniform velocity of 5ms-1 on a smooth horizontal surface. The engine of the vehicle stops aft 250 m . wat is the frictional force that opposes the motion of the vehicles.?

i thought when the ques says SMOOTH HORIZONTAL SURFACE,it means that i can neglect friction?

Answer 1

If there is no friction, the vehicle will not come to a stop isn't it?

Anyway the answer to your question is:

v^2 = u^2 + 2as

0 = 25 + 2(250)a

a = -0.01 ms-2

F=ma=1800*0.01=18 N

Answer 2

As per standard terminology, if the question says smooth, it means that you can neglect friction. But in this problem, the author who wrote the problem has made a mistake. He has unnecessarily used the word smooth. He should only say horizontal surface.

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Answer 3

yeah sometimes u can neglect it and sometimes you cant some authors suck... is there any other info given or just the engine stops after 250m? or car stops?

number one i dont really understand but i understand the second guys work...seems logical enough..