Conservation of energy on a frictionless ramp
A cart starts from rest at the top of a frictionless ramp 5 m high. Using g = 10 m/s², what is its speed at the bottom?
Answer C: explanation for every choice
A
This equates speed with height, which has no physical basis.
B
This uses √(gh), dropping the factor of 2.
C
Correct. mgh = ½mv², so v = √(2gh) = √(2 × 10 × 5) = 10 m/s.
D
This is 2gh without taking the square root.
Takeawaymgh = ½mv², so v = √(2gh), independent of mass.
Equation usedKinetic and gravitational potential energy
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