yes. this is the baseline understanding for rotational motion. Think of driving a car, if you turn the wheel of the car then you are directing the frictional force near perpendicular to your velocity and thus "turn" the car.
More precisely, the car's acceleration is radial while its velocity is tangential and thus the car is following a rotational path, during the turning phase of travel.
Yes. The typical case is of an object moving around in a circle.
a vector quantity has both direction (sign) and magnitude like displacement towards right or left (direction) and has a certain value (magnitude)
polarized light
If the equal and opposite forces are separated by a certain distance they are called as couple. If the equal and opposite forces are not seperated by a certain distance their resultant is zero as per Parallelogram Law of Vector Addition.
A change in position in a certain amount of time is called motion.
An antonym (opposite) for certain is maybe not certain
There can be.
no
foliation
foliation
It could be, but without the diagram it is not possible to be certain.
no because it is what it is today and tomorrow and always sorry
just see if its a right angle
Velocity. Velocity also has a vector, or certain direction.
Normal Force
Sure. That just means that when you set up the problem, you indicated angles to be measured in a certain direction from the reference point, and the answer turned out to be an angle in the other direction from the reference.
wind.
It is a plane perpendicular to the lens at the focal distance from the lens. All parallel light entering the lens from a certain direction falls on a single point somewhere on this plane. Where the point of light falls depends on what angle the "wall" of light enters the lens.