Here in question 3 I am unable to get the velocity from the derivative. Please show me how the velocity is obtained. 
 
 

Asked by Varsneya Srinivas | 2nd Jul, 2016, 09:39: AM

Expert Answer:

We know that velocity is the rate of change of displacemnet.
Given that
begin mathsize 12px style straight x equals 3 plus 8 straight t plus 7 straight t squared
fraction numerator d straight x to the power of straight n over denominator d straight t end fraction equals straight n space straight x to the power of straight n minus straight i end exponent
Differentiating space the space above space equation space wrt comma space we space get
rightwards arrow fraction numerator d straight x over denominator d straight t end fraction equals fraction numerator d open parentheses 3 close parentheses over denominator d straight t end fraction plus fraction numerator d open parentheses 8 straight t close parentheses over denominator d straight t end fraction plus fraction numerator d open parentheses 7 straight t squared close parentheses over denominator d straight t end fraction
rightwards arrow fraction numerator d straight x over denominator d straight t end fraction equals 8 plus 2 cross times 7 straight t space....... space left parenthesis Equation space 1 right parenthesis
Given space that space straight t space equals space 2 straight s
Substituing space in space equation space left parenthesis 1 right parenthesis comma space we space get
rightwards arrow fraction numerator d straight x over denominator d straight t end fraction equals straight v equals 8 plus 2 cross times 7 cross times open parentheses 2 close parentheses space
rightwards arrow straight v equals 36 space straight m divided by straight s
In space straight a space similar space way comma space acceleration space is space the space rate space of space change space of space velocity. space
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Answered by Yashvanti Jain | 4th Jul, 2016, 10:30: AM