Question

The maximum and minimum magnitudes ofthe resultant of two forces are 17 Newton and 7 Newton respectively, If these two forces are acting at right angle to each other, then the value of resultant of these forces in Newton will be:

(A) 10 (B) 12 (C) 13 (D) 24
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Answer 1

We know, we get maximum resultant of two vectors when they are acting in the same direction,

So,

A+B = 17N...(ii)

and we get minimum when they are acting in opposite direction, that is,

A- B = 7N.....(i)

Adding, eq(i) and (ii) we get,

A+B = 17N

A-B = 7N

___________

2A = 24N

A = 12N

then,

B = 17N -12N = 5N

Now when ∅ = 90°

Resultant = √(A²+B²)

=>√(12²+5²)

=>√(144+25)

=>√169

=>13N

Correct option is C)13N

Cheers!

Answer 2

Max result of 2 vectors is when they are parallel and Minimum result is when they are anti parallel.Such that the former is equal to sum of 2 vectors and latter is difference of same..

let a and b be the forces such that a>b

a+b=17

a-b=7

Solve to get

a=12(newton)

b=5(newton)

At right angle

Resultant of vector perpendicularly inclined is given by sqr.root(a^2+b^2)

so Resultant must be 13 here (unit newton)

Option c is correct

HOPE IT HELPS

EARLY ANSWER CREDITS......UPAR DEKHO :-)