Answer:
The direction of a magnetic field is by convention, the direction towards which the northpole of a compass needle points when placed under the influence of the magnetic field at any location.
Explanation:
A Magnetic field is a vectorial force field.
As such, the direction of such a field is very important when describing it.
The direction of a magnetic field is by convention, the direction towards which the northpole of a compass needle points when placed under the influence of the magnetic field at any location.
The direction of a magnetic field may be further described using magnetic field lines .
PS: An important feature of magnets is that like poles repel and unlike poles attract. Just an additional detail.
Given data:
* The acceleration of the runner is,
![a=3.2ms^{-2}](https://tex.z-dn.net/?f=a%3D3.2ms%5E%7B-2%7D)
* The initial velocity of the runner is,
![u=9.23ms^{-1}](https://tex.z-dn.net/?f=u%3D9.23ms%5E%7B-1%7D)
* The time given is,
![t=6.7s](https://tex.z-dn.net/?f=t%3D6.7s)
Solution:
By the kinematics equation, the final velocity of the runner is,
![v-u=at](https://tex.z-dn.net/?f=v-u%3Dat)
where v is the final velocity,
Substituting the known values,
![\begin{gathered} v-9.23=3.2\times6.7 \\ v-9.23=21.44 \\ v=21.44+9.23 \\ v=30.67ms^{-1} \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20v-9.23%3D3.2%5Ctimes6.7%20%5C%5C%20v-9.23%3D21.44%20%5C%5C%20v%3D21.44%2B9.23%20%5C%5C%20v%3D30.67ms%5E%7B-1%7D%20%5Cend%7Bgathered%7D)
Thus, the final velocity of the runner is 30.67 m/s.