Q&A - Ask Doubts and Get Answers
Q

A car moving along a straight highway with speed 126

And also say how to handle "how long will it take " type of questions.

Please answer these 3 questions.

4. A car along a straight highway with speed 126 km h-l is brought to a halt within a distance of 200m, What is the retardation of the car (assumed uniform) and how long does it take for the car to stop? 5. A car is moving with speed u Driver of the car sees red traffic light, His reaction time is t, then find out the distance travelled by the car after the instant when the driver decided to apply brakes 6.Assume uniform retardation 'a' after applying breaks. If a body starts from rest and travels 120cm in the 6th second then what is the acceleration
Answers (3)
Views
S safeer

u^2=v^2-2as....(1)\\s=ut+0.5at^2.....(2)\\u=126km/h=35m/s\\final\ velocity\ is\ zero\\from\ (1)\\a=-3.0625\where\ -\ represents\ retardation\\from(2)\\v=u+at\\t=35/3.0625\ =11.43

 

S safeer

s=ut+0.5at^2 s\ at\ 6th\ sec \ is \ s_6-s_5\\u=0\\0.5a\times36-0.5a\times25=1.2\\a=0.218

S safeer

s we can find using

u^2=v^2-2as

and t from v=u+at

where t=reaction time + time taken to stop

 

Exams
Articles
Questions