Final answer:
To find the speed at point 4 of the roller coaster, we can use the principle of conservation of energy and the equation for kinetic energy.
Step-by-step explanation:
To find the speed at point 4 of the roller coaster, we can use the principle of conservation of energy. The potential energy at point 2 is converted into kinetic energy at point 4. Given that h2 = 20 m and h3 = 35 m, we can calculate the change in potential energy between points 2 and 4:
ΔPE = mgh = mg(h3 - h2)
Next, we can equate the change in potential energy to the change in kinetic energy:
ΔPE = ΔKE
Finally, we can solve for the speed at point 4 using the equation for kinetic energy:
KE = 1/2mv^2
By substituting the known values and solving for v, we can find the speed at point 4.