# the weight against gravitational force, physics homework help

### 1.You do work on something when you lift if against gravity. Explain how work relates to gravitational potential energy using at least two complete content related sentences.If the lifted object is released, describe the change in energy. Be sure to define all terms used in both questions.

2.In terms of momentum change, explain why it is best to “give” when catching a baseball.Provide at least TWO other examples of situations in which you want “give”.

3.A boy fires a table tennis launcher. Briefly describe the forces and impulses on the launcher and the ball. Explain which has momentum.Explain which is moving faster.Be sure to use at least 3 to 4 complete content related sentences.

4.Suppose you are on an airplane moving at high speed.If you flip a coin straight up it will land in your lap rather than a great distance behind you.Explain why this is true and include any laws that help prove your point.Your answer should be at least 3 to 4 complete content related sentences.

5.What is terminal speed? When a skydiver has reached terminal speed, what is the are resistance equal to?What is the skydiver’s acceleration?Be sure to use at least 3 to 4 complete content related sentences.

6.A force is a push or a pull.Newton’s third law further defines the meaning of force.Be sure to explain using at least 3 to 4 complete content related sentences.

7.The sun radiates about 3.6 x 1026 joules of energy each second.How much mass does the sun lose each second?Show all of your work and be sure all numbers must be clearing identified and explain in your work.

8.Provide the time dilation equation found in Section 15.4 of the text.Explain each step of the derivation.

9.You sit at the outer rim of a Ferris wheel that rotates 2 revolutions per minute (RPM).What would your rotational speed be if you were instead clinging to a position halfway from the center to the outer rim?Be sure to provide at least 3 to 4 complete content related sentences and show any work needed to support your answer.

10.At the outer edge of a rotating space habitat, 130 m from the center, the rotational acceleration is g.What is the rotational acceleration at a distance of 65 m from the center of the habitat? Be sure to show all work and steps to support your answer.

11.A car traveling at 60 km/h will skid 30 m when its brakes are locked.If the same care is traveling at 180 km/h, what will be the skidding distance? Be sure to show all work to support your answer.

12.At what height does a 1000-kg mass have a potential energy of 1J relative to the ground?Be sure to show all work to support your answer.

13.A bicycle travels 15 km in 30 minutes. What is its average speed?Be sure to show all work to support your answer.

14.What is the average acceleration of a car that goes from rest to 60 km/h in 8 seconds?Be sure to show all work to support your answer.

15.What speed must you toss a ball straight up so it takes 4 s to return to you?Be sure to show all work to support your answer.

16.Assume that a 15-kg ball moving at 8 m/s strikes a wall perpendicularly and rebounds elastically at the same speed.What is the amount of impulse given to the wall? Be sure to show all work to support your answer.

17.A net force of 1.0N acts on a 4.0-kg object, initially at rest, for 4.0 seconds.What is the distance the object moves during the same time?Be sure to show all work to support your answer.

18.What is the energy equivalent of 5.0 kg of mass?Be sure to show all work to support your answer.