Answer:
B) 40 km West
Explanation:
Let position of B is origin so with respect of City B the position of A is given as
south of city B
now Bus starts from City A and travels a distance of 50 km at 37 degree North of East to reach city C
so it is


now the position of C is given with respect to A
in order to find the position of C with respect to B we can say



so in order to reach at city B from city C bus has to travel 40 km towards West
Answer:. Option c
Explanation: the speed of an electromagnetic wave is simply the vector product of the magnetic field and the electric field.
The direction of the velocity is the direction of the electromagnetic wave.
The wave is already moving towards the negative y axis (-j) and the magnetic field is already pointing towards the positive x axis (i)
From cross product of unit vectors
i × j = k
i × k = - j
With the second identity, we can see that the electric field will be pointing towards the positive of the x axis (k).
Option c is validated
Answer:

Explanation:
This is an exercise where you need to use the concepts of <em>free fall objects</em>
Our <u>knowable variables</u> are initial high, initial velocity and the acceleration due to gravity:



At the end of the motion, the <u><em>rock hits the ground</em></u> making the final high y=0m

If we <em>evaluate the equation</em>:

This is a classic form of <u><em>Quadratic Formula</em></u>, we can solve it using:




Since the <u><em>time can not be negative</em></u>, the <em>reasonable answer</em> is
