Mini-Quiz: Work Against Gravity to Lift an Object

1. How much force is needed to project an object upward at a constant velocity?

   More than its weightGood try, but not right. Select another answer. Equal to its weightCorrect. You are a gravity expert. Less than its weightSorry, not correct. Try another button.

2. Why must inertia be taken into account when lifting a stationary object?

   It is only a factor when dropping an objectSorry, not correct. Try another button. Inertia is required if the object is very heavyOops! Wrong answer. Re-read the question and try again. Resistance from inertia comes when the object accelerates from zero to some velocityThat is Correct. You know about work.

3. Why is air resistance a factor in projecting a rocket upwards?

   It is only a factor if the force from gravity becomes zeroGood try, but not right. Select another answer. High velocities greatly increases the air resistance forceCorrect. You are a gravity expert. It is needed for the rocket to return to EarthOops! Wrong answer. Re-read the question and try again.

Pick an answer to see instant feedback. Re-read the lesson if you miss one.