Ignoring air resistance, the time taken to return to the launch point after being thrown upward at 20 m/s is:

A correct analysis gives 4 s when magnitude, direction, units and conditions are considered. The question tests whether the learner can dist...

A correct analysis gives 4 s when magnitude, direction, units and conditions are considered. The question tests whether the learner can distinguish the required quantity from related ideas and use the stated information without adding unsupported assumptions. The alternatives 2 s, 10 s, and 20 s do not satisfy the governing definition, graph interpretation, direction convention, or numerical relationship in this case. In examinations, identify the known quantities, keep SI units consistent, select a positive direction where needed, and apply the appropriate definition or equation. This also checks that the answer has a sensible magnitude and unit.