A vector of magnitude 3 CANNOT be added to a vector of magnitude 4 so that the magnitude of the resultant is?

Question

but the official-correct answer is ZERO, and i don't know how the h**l they got that :(

Answer 1

I agree with Steve!!!  

A vector of magnitude 3 CANNOT be added to a vector of magnitude 4 so that the magnitude of the resultant is.. .less than 1 or larger than 7.

Answer 2

Steve and UV correctly stated the mathematics.

However, if the question is a multiple choice question, with "zero" being one choice and all the rest between 1 and 7, then obviously "zero" is the only correct answer.

So whether the answer makes sense depends on how the question is constructed.

Answer 3

greater than 8 or less than -1

Answer 4

Actually the resultant vector has to be in the range from +7 to +1, assuming they're added in the order you state.

Given the CANNOT in the ?, EVERYTHING outside that range (including zero) will be a correct answer.  Zero is NOT a unique answer.

I've seen a number of so-called 'correct' answers provided by 'them' turn into dog doo-doo under scrutiny here.