Question

Two forces of magnitudes 8N and 15N act at a point,if the resultant force is 17N,the angle between forces is equal to:

Answer 1

The angle is 90degrees it is an orthogonal vector as the resultant vector = root of (8^2+15^2)

Answer 2

The resultant of two vectors:

P

and

Q

​

is given by

R=

P

2

+Q

2

+2PQcosθ

​

where, P and Q are magnitudes of two vectors and θ is the angle between two vectors.

Here θ=? P=8N Q=15N R=17N

Therefore,

17=

8

2

+15

2

+2×8×15cosθ

​

289=64+225+240cosθ

289=289+240cosθ

289−289=240cosθ

cosθ=0

cosθ=cos90

θ=90

0

Step-by-step explanation: