The height of hills affect the roller coaster by the amount of gravitational potential energy that is collected while rising.   Therefore, the higher the hill, the greater the potential energy. The greater the gravitational potential energy, the more speed (Kinetic Energy) is able to be used. As the object gets closer to the ground, its potential energy decreases while its kinetic energy increases. This is located in two places of the coaster where the marble proceeds up in a vertical direction. This makes the marble slow down , but gains energy for the next part of the roller coaster. When the train begins to climb the next hill on the track, the train's kinetic energy is converted back into potential energy, decreasing the train's velocity. This process of converting kinetic energy to potential energy and back to kinetic energy continues with each hill. 

Sara Lengawi

A roller coaster reaches its top speed at the end of the ride, where the force of gravity has converted most of the stored energy into speed. The potential energy increases as the chain pulls the train to the top of the first hill. It reaches its maximum in the fraction. As gravity pulls the train downwarod, it converts potential energy to kinetic.

Temperature – The lower the temperature the slower the train.

Wind – The direction and speed of the wind affects the speed of the train (and sometimes forces parks to close the ride until conditions are safe to operate).

Load – A loaded train (with weighted water dummies or people) will go faster than an unloaded train.

Wheel Bearing Clearance – Correct assembly of the wheels reduces internal friction and heat.

Wheel Bearing Lubrication – The amount and type of grease affects the speed of the train.

Track Lubrication – If the tack is lubricated the train will travel faster due to less frictional head losses. Track lubrication also prevents excessive wear to the rails and the wheels, especially those of wooden roller coasters.

These factors play larger or smaller roles depending on what type of coaster you are looking at, wood or steel. For example, track lubrication is primarily a concern of wooden coasters whereas wheel material is a bigger factor for steel rides.

Some of these factors can be controlled by the park, such as the number of guests they allow on the train as well as when to use lubrication. Other factors cannot be controlled, such as temperature, wind (unless built entirely indoors), and the natural lubrication affect of rain.

Time of day is another factor of influence, especially on a wooden coaster.  This is usually directly related to temperature. In the morning, the trains have been sitting cold all night and haven’t warmed up. Often times towards the end of the year, amusement parks will “deadweight” the coasters just to get them around the course. It’s due to the temperature of the wheels- if they’re cold the ride runs a vast amount slower than if the ride’s been running all day. It doesn’t make as much of a difference if the sun has been out for a while and the track is warm, because then the wheels will warm up faster. It’s because of this that enthusiasts like to ride at night; warm wheels mean faster rides.

There are some causes and effect for the roller coaster such as the slope :  a surface of which one end or side is at a higher level than another. By preventing energy to be wasted ; Choose an energy-efficient roller coaster . The last thing is the height related to gravitational potential energy. That things may effect the speed of the roller coaster. This essay will discuss about that in details. 

Every thing has causes and effects and all the given are : the slope , by preventing energy to be wasted and the height. That are the main causes and effects. So it can be fixed by using physics laws .