The magnitude of two forces, which when acting at right angle produce resultant force of $$\sqrt {10} $$ kg and when acting at 60° produce resultant of $$\sqrt {13} $$ kg. These forces are
A. 2 and $$\sqrt 6 $$ kg
B. 3 and 1 kg
C. $$\sqrt 5\,$$ and $$\sqrt 5 $$ kg
D. 2 and 5 kg
Answer: Option C
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The weight of a body is due to
A. Centripetal force of earth
B. Gravitational pull exerted by the earth
C. Force of attraction experienced by par-ticles
D. Gravitational force of attraction towards the centre of the earth
The product of either force of couple with the arm of the couple is called
A. Resultant couple
B. Moment of the forces
C. Resulting couple
D. Moment of the couple
A. Density of metal can’t be determined
B. Metal is twice as dense as water
C. Metal will float in water
D. Metal is twice as dense as unknown fluid
Coulomb friction is the friction between
A. Bodies having relative motion
B. Two dry surfaces
C. Two lubricated surfaces
D. Solids and liquids
correct option is B
3 and 1
Here v10 means root 10
So its square is 10
v13 means root 13
So its square is 13
Now refer to Muhammad Saqib's answer
Mohammad saqib why aren't you using square of resultant?
this is wrong answer.....right answer is 3kg and 1kg
Answer is wrong.it should be 3&1.
B. 3 and 1 kg
Given answer is incorrect
Let the forces be f1 and f2
f1²+f2²=10
as the angle between them is 90 degrees
when angle is 60
f1²+f2²+2*f1*f2*cos(60)=13
10+f1*f2=13
3=f1*f2
(f1+f2)²=f1²+f2²+2*f1*f2=10+6=16
f1+f2=4...(1)
f1-f2=√((f1+f2)²-4f1*f2)=2...(2)
from (1) and (2) u get
f1= 3 N f2= 1 N
How's the answer is coming?