What has changed is the velocity. This is happen because :
Hi ! Here I will discuss about velocity and speed. velocity is different from speed. Velocity depends on displacement (movement relative to the starting point) divided by the value of time. On the other hand, speed depends only on distance (how far the object is moving) regardless of the starting point of the movement. Therefore, velocity is called a vector quantity (a value that is easily influenced by direction), while speed is called a scalar quantity because it does not care about direction.
Why do I say there that the resultant velocity is 15√2 m/s ? This is because there is a double direction that makes it necessary to calculate the resultant using the formula:
[tex] \sf{\sum v = \sqrt{(v_1)^2 + (v_2)^2 + 2(v_1)(v_2) \cos(\theta)}} [/tex] >> [tex] \sf{\theta} [/tex] = 90°
[tex] \sf{\sum v = \sqrt{(15)^2 + (15)^2 + 2(15)(15) \cos(90^o)}} [/tex]
[tex] \sf{\sum v = \sqrt{225 + 225 + 2(15)(15) (0)}} [/tex]
[tex] \sf{\sum v = \sqrt{450 + 0}} [/tex]
[tex] \sf{\sum v = \sqrt{225 \times 2}} [/tex]
[tex] \sf{\sum v = 15 \sqrt{2} \: m/s} [/tex] (Q.E.D)
