00:01
In this position, we have cara traveling along the street portion of the road, the speed of 25 meters per second, 30 degrees to the horizontal, and then vb, carb is moving at 15 medias per second, travels along the circular portion, and the angle is 15 degrees from the horizontal.
00:23
We need to find a velocity of v relative to cara, okay? so this is a relative motion problem.
00:31
So first thing to do is to write down the velocities of a and b in vector form.
00:39
So va is equal to 25 cosine 30 degrees i had minus sine 30 degrees j hat and this is equal to 12 .5 times 3 i head meters per second and then vb is equal to 15 times cosine 15 degrees i had minus sign 15 degrees j hat okay meters per second and so the velocity of b relative to a is defined to b v b minus va okay so so just put down the terms properly 15 hosy 15 degrees minus 12 .5 root 3, i hat plus minus 15 sine 15 degrees plus 12 .5 j hat.
01:54
You calculate each components.
01:57
Using calculator you get negative 7 .16 i.
02:02
Head plus 8 .62 j heads a meters per second.
02:09
So from here we can calculate the magnitude of the relative velocity so you square the components and sum them up and take the square roots...