Answer:
12.65 m/s
Explanation:
When friction is ignored, if the car travels from 18m hill to the bottom of the hill, afterwards it travels up to a 10m hill, then overall it has traveled a distance of 18 - 10 = 8 m vertically.
If the car starts from rest, then its potential energy is converted to kinetic energy:
[tex]E_p = E_k[/tex]
[tex]mgh = mv^2/2[/tex]
where m is the car mass and h is the vertical distance traveled, v is the car velocity at 10m hill
Let g = 10m/s^2. We can cancel m from both sides of the equation:
[tex]gh = v^2/2[/tex]
[tex]v^2 = 2gh = 2*10*8 = 160[/tex]
[tex]v^2 = 160[/tex]
[tex]v = \sqrt{160} = 12.65 m/s[/tex]