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If speed (v) and time (t) are related as t 2 -10vt+10000=0; then what can be the values of v? a) All values more than or equal to 20 units b) All values less than 20 units c) All positive values are possible for v d) No value of v can satisfy the given expression

If speed (v) and time (t) are related as t2-10vt+10000=0; then what can be the values of v?


a) All values more than or equal to 20 units


b) All values less than 20 units


c) All positive values are possible for v


d) No value of v can satisfy the given expression

Grade:11

1 Answers

Badiuddin askIITians.ismu Expert
148 Points
14 years ago

Dear  Abhingya Patra

t2-10vt+10000=0

this equation is quadretic in time.

since time t is real positive value

solve this equation for t

 t = {10v ± √(10v)2 -4*1*10000}/2

    ={10v ± 10√v2 -400}/2

    =5v ± 5√(v2 -400)

for real value of t

v2 -400 ≥0

(v-20)(v+20) ≥0

 V ≤-20  or v≥20

but negative value of t will give negative time which is not possible

so v≥20 is the solution

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