A 2.0 kg box slides down a frictionless ramp that is 3.0 m high and 5.0 m long. What is the speed of the box at the bottom of the ramp?

Core Concept

This is a conservation of energy problem. The potential energy at the top (mgh) converts to kinetic energy at the bottom (½mv²). Setting them equal: mgh = ½mv². The mass cancels out, giving v = √(2gh) = √(2 × 9.8 × 3.0) = 7.7 m/s. Option A is incorrect because it uses √(gh) instead of √(2gh). Option C is incorrect because it uses g instead of √(2gh). Option D is incorrect because it uses √(4gh) instead of √(2gh).