We know that speed is a scalar unit while velocity is a vector. The signs are mostly concerned with the magnitude that the car should travel in, the direction is not as important.
Hope I helped :)
Answer:
I. Speed = 20m/s
II. Velocity = 20m/s due North.
Explanation:
<u>Given the following data;</u>
Distance = 40m
Time = 2secs
To find the speed;
Mathematically, speed is given by the formula;

Substituting into the equation, we have;

<em>Speed = 20m/s.</em>
In physics, we use the same formula for calculating speed and velocity. The only difference is that speed is a scalar quantity and as such has magnitude but no direction while velocity is a vector quantity and as such it has both magnitude and direction.

<em>Therefore, the velocity is 20m/s due North</em>.
Answer:
(a) has the highest frequency
Explanation:
E = hf...where E(is the energy of a photon);h(is the planck's constant) and f is the frequency of the photon
Whereby this formula shows us that energy of a photon is directly proportional to its frequency
So hence if the energy is high then the frequency of the photon is also high