Question

Closed

Answer 1

minimum time is for the constant maximum acceleration
am i right?

Answer 2

yes

Answer 3

and initial velocity is zero i mean motorcycle is at rest at the start point

Answer 4

yeah

Answer 5

then i think we can use this formula
\[x=\frac{1}{2} a t^2\]
x=1500 m
a= 5 m/s^2
t=?

Answer 6

wow..i just didn't change km to m lol :/
so i got root 15 nvm o.o thanks

Answer 7

welcome dear

Answer 8

hey..im getting the wrong answer!
it should be 30 but im getting nearly 25s which is wrong! @mukushla
@Vaidehi09

Answer 9

@Vaidehi09
could u plz check it

Answer 10

i already did. i also got approx 25s. are we wrong in assuming u = 0 ?

Answer 11

motorcycle is at rest at the start point
thats a true assumption

Answer 12

true. and ur approach seems right to me. so the answer ought to be approx 25s.

Answer 13

nope there is 25s as answer too but its 30!

Answer 14

check the question it will be
the engine of a motorcycle can produce a maximum acceleration of 5 m/s^2. its brakes can produce a maximum retardation of 10 m/s^2. What is the minimum time in which it can c over a distance of 1.5 km?

Answer 15

@mukushla why do we need the retardation value? we have to find the minimum time in which it covers 1.5km. that doesn't mean that it needs to come to a stop after covering that distance, right?

Answer 16

right

Answer 17

maybe its a misprint? because if we go backwards, and take t = 30, then we get a = 3.33. so if we want to find the min time, why would we not use the max accel?

Answer 18

solve it by retardation value

Answer 19

what will u get?

Answer 20

then u'll get -t^2 = 300......we can't solve this coz of the minus sign.