Adding force vectors and then calculating acceleration.

[agoogler]

Homework Statement

Two forces act simultaneously on a body of mass 15 gram. The magnitudes of the
forces are 1 Newton and 3 Newton, and the angle between them is 60° as shown. Find the
magnitude of the acceleration of the body. Express your answer in m/s2 and to the nearest
integer.

Homework Equations

F = ma

The Attempt at a Solution

The sum of the two force vectors is √{1+9+(6*1/2)} =√13 .
Thus a =√13/(15/1000 kg) = ~240 .
But the answer is very far off. Where have I went wrong ? Please help.

 

[barryj]

I think you are correct.

 

[haruspex]

So do I. What answer is given?

 

[agoogler]

So do I. What answer is given?

The answer given is 67 .

 

[haruspex]

The answer given is 67 .

You'd get that acceleration from a force of 1N on 15g.

 

[agoogler]

You'd get that acceleration from a force of 1N on 15g.

Right ! I didn't notice that . So probably its a mistake in answer sheet.