00:01
For this problem on the topic of conservation of energy, we are told that a runaway truck is moving downhill at a speed of 130 kilometers per hour, and its brakes have failed.
00:11
The driver steers up a frictionless emergency escape ramp that has an inclination of 15 degrees.
00:18
If we are given the truck's mass to be 1 .2 times 10 to the 4kg, we want to find the minimum length the ramp has for the truck to completely stop along it.
00:29
We want to know if this minimum length will increase decrease or remain the same, if the truck's mass is decreased and then its speed is decreased.
00:42
So now the truck with fail brakes is moving up an escape ramp and in order for it to come to a complete stop, all of its kinetic energy must be converted to gravitational potential energy.
00:51
Now if we ignore any work done by friction in the initial speed of the truck, vi, we need to find in si units and we have vi to be 100.
01:02
130 kilometers an hour times 1000 over 3 ,600, which gives us an initial speed to be 36 .1 meters per second.
01:16
Now when it comes to a stop, its kinetic and potential energies will be 0 and mgh, respectively...