Practice portal › Motion in a Plane › Vector Addition and the Resultant
Asked in NEET 1988 · Magnitude of the resultant
Given: A=3, B=4, C=5 with A⃗+B⃗=C⃗.
Idea: square the vector equation so the angle appears through the cross term.
C²=A²+B²+2AB cos θ.
25=9+16+2(3)(4)cos θ.
25=25+24 cos θ, so 24 cos θ=0.
cos θ=0, giving θ=π/2: the familiar 3-4-5 right triangle.
Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.
Practise this with a timer