A block is pressed against an ideal horizontal spring (spring constant k) so that the…
PHYSICS · Multi-part · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
A block is pressed against an ideal horizontal spring (spring constant k) so that the spring is compressed a fixed distance x from its natural length. When released from rest, the block slides off the spring, moves across a frictionless surface, and then ascends a smooth, frictionless hill that rises to a maximum height h_max above the original spring level. Three different blocks—A, B, and C—have masses m, 2m, and m⁄2, respectively, and are each subjected to the same initial compression x of the same spring in separate, otherwise identical trials.
(a) Rank the magnitudes of the initial elastic potential energies stored in the spring for the three trials. Justify your answer qualitatively.
(b) Rank the speeds of the blocks as they leave the spring (immediately after losing contact) from greatest to least. Provide a qualitative justification that explicitly references energy transformations.
(c) Rank the maximum heights h_max reached by the blocks on the hill from greatest to least. Provide a clear qualitative explanation for your ranking.
(d) A student argues that the lightest block should reach the highest point because it is easiest to lift. Critically evaluate this statement using energy reasoning drawn from your answers to parts (a)–(c).