00:05Numerical number 6 of unit 1 is 2 students derive following equations in which x refers
00:14to distance travelled, v the speed, the acceleration means a the acceleration and t the time and
00:27the subscript 0 means a quantity at time t is equal to 0, a x is equal to v into
00:39t square
00:39plus 2 a t and b x is equal to v naught t plus 2 a t square which of
00:49these could possibly
00:51be correct according to the dimensional check, a incorrect b correct.
01:03So, first we will check dimensionally a for solution is a is given which is x is equal
01:17to v into t square plus 2 a t here x is distance so its unit is meter and the
01:30v is speed so
01:32its unit is meter per second into t square means t is time so square on second plus 2 a
01:43is acceleration
01:43so its unit is meter per second square multiplied with time the unit of time is second so meter
01:52will be equal to as the square will be get cancelled with this second so this will be meter into
02:03per second so this will be meter per second is the dimension of meter is length and the dimension of
02:21meter is length and
02:22the dimension of meter is length and second means time t plus number ka dimension nahi hota there will be
02:31no dimension of number
02:32so it will be length upon time is this is left hand side and this is right hand side so
02:43left hand side is not equal to right hand side so it is dimensionally incorrect
03:00b is given as x is equal to v 0 t plus 2 a t square. x is distance so
03:16its unit is meter and this is a speed so its unit is meter per second.
03:22multiplied with time the unit of time is second plus 2 into acceleration the
03:28unit of acceleration is meter per second square multiplied with t square means
03:36second square because the unit of time is second so meter will be equal to this
03:43second will be cancelled with this second so meter plus 2 second square will be
03:51get cancelled with second square so 2 into m it will be 2m
03:57yahan par 2m hai aur yeh m hai so it will be 1m plus 2m it will be 3m numbers
04:08ka
04:09koi dimension nahi hota there will be no dimension of numbers so this is meter and
04:16this is also meter so it's dimension is L and it's dimension is also L so both
04:24sides are equal means both sides have same dimensions so we can also write this as
04:32left hand side is equal to right hand side so it is dimensionally correct a is
04:42dimensionally incorrect but B is dimensionally correct
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