A railway car of mass 20 tonnes moves with an initial speed of 54km/hr. On applying brakes, a constant negative acceleration of 0.3m/s2 is produced.
(i) What is the breaking force acting on the car?
(ii) In what time it will stop?
(iii) What distance will be covered by the car before if finally stops?
CLASS - XI PHYSICS (Laws of Motion)
Answers
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(i) Friction
(ii)Time=Speed/ acceleration
54km/h=15m/s
=15m/s / 0.3m/s2
Time =50s
(iii)Distance=Speed*Time
50s=0.83m=0.138h
=54*0.138
7.4km
(ii)Time=Speed/ acceleration
54km/h=15m/s
=15m/s / 0.3m/s2
Time =50s
(iii)Distance=Speed*Time
50s=0.83m=0.138h
=54*0.138
7.4km
vaibhavmn:
I think the ans is wrong
only b is correct...dude, you don't even know the basic formulas....
Sorry it is Frictional Force
what is wrong
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