Question

please answer this question.....with proper solution..​

Answer 1

Explanation:

when it is said retardation either you take negetive sign or just take (a) positive.... because you are told that is is retardation..and if it is said acceleration you can take positive(a) for that case you will find negetive acceleration(same thing but negetive of retardation)

Answer 2

Answer: +0.5 m/s

Explanation:

v=0

u=10 m/s

t= 20 s

a=?

we know that,

                        v= u-at              (- for retardation , as v <u)

                       => 0=10-20*a    

                      => -20*a=0-10

                      =>-10= -20*a

                       => a=10/20

                      =>a=0.5 m/s

   but we have taken a to be retardation so ret.=0.5 m/s

                                                                    or acc.= -0.5 m/s.