A student standing at the edge of a cliff that is above level ground throws a rock…
PHYSICS · Multi-part · CBSE · Physics · Motion in a Plane · Motion in a Plane
Problem
A student standing at the edge of a cliff that is 20m above level ground throws a rock with an initial speed of 15ms−1 at an angle of 40∘ above the horizontal. Neglect air resistance.
(a) Derive an expression for the time interval between the rock’s launch and the instant it reaches ground level.
(b) Using your expression from part (a), calculate the horizontal distance from the base of the cliff to the point where the rock lands.
(c) The student repeats the throw with the same launch speed but an angle of 55∘. Without doing a complete new calculation, determine which launch angle, 40∘ or 55∘, results in a greater horizontal distance. Justify your answer qualitatively.
(d) Describe qualitatively how the horizontal distance found in part (b) would change if the experiment were performed on a planet where the free-fall acceleration is one-sixth of Earth’s value, all other conditions being the same.