Answer:
Normal Force is usually perpendicular to the movement and static friction usually means that there is no movement.
Explanation:
The work donde by any force on an object is equal to the displacement of the object multiplied by the component of the force that is in the direction of the displacement.
Normal force is usually perpendicular to the movement, so there is no component in the direction of the displacement. This is why it is zero in most circumstances.
<em>Static</em> friction on the other hand, usually means that there is no movement at all (it's static). It means that there is no displacement between the object and ground (in most cases). If there is no displacement, there is no work.
They should be bigger as if it is hot the tracks will expand as it is made of metal and then there is more room for it to expand or contract
W=mgh
W=(6)(9.8)(4)
W= 235.2J
An example of the use of expansion of materials when they are heated is in
Thermometers. Thermometer is an instrument which is used to measure the
temperature of a place.
It contains mercury which expands as temperature increases. This is used
to accurately determine the temperature of an object.
The disadvantage of expansion of materials when they are heated can be
seen in roads as there is expansion of the surface as a result of heat
exposure leads to roads being rough thereby incurring more costs for
repairs.
Read more about Heat expansion on brainly.com/question/1166774
