What if two children push a swing at the same time? Would the swing go higher? Yes, together their force would be more. It is common for forces to be combined. Most objects on Earth have at least two forces acting on them. Do you know what one of them is? Of course, that force is gravity. How many forces do you have on you right now? Gravity pulls you down toward the center of Earth. Your legs exert a downward force. They hold you up against the pull of gravity. Consider the example in Figure 1.3. A book is resting on a table. Gravity pulls the book downward. It has a force of 20 newtons. At the same time, the table pushes the book upward. Its force is also 20 newtons. The table opposes the pull of gravity.

What forces acts on a book on a table?

Madrid, Spain (CNN) -- Relatives of a woman killed in a Spanish airline crash were erroneously given the remains of another victim, and then were asked by authorities to return them, CNN partner network CNN+ reported Thursday. The victims of the crash were first laid out at a Madria convention center. A Madrid judge has opened an investigation into the error, and judicial sources say the initial indication is that the mixup occurred not in the proper identification of the victim, but in delivering the wrong remains to the family in question, CNN+ reported. The family Wednesday received an urn numbered 104, and were told it contained the ashes of their loved one, Pilar Gonzalez Ferreira, who died in the crash. But as the family was preparing to leave Madrid, officials called to tell them about the error and asked for the return of urn 104, CNN+ reported. Instead of urn 104, the family was supposed to have received urn 134, which actually contains the remains of Pilar Gonzalez, CNN+ reported, citing judicial sources and another family which also lost a relative in the crash. The Spanair MD82 jet crashed last week at Madrid's airport as the plane was trying to take off, killing 154 people. The aircraft, bound for Spain's Canary Islands, managed to rise only slightly before coming down quickly to the right of the runway, its tail section hitting the ground first, just off the asphalt. Then the out-of-control plane skidded and bounced at least three times as it careered 1,200 meters (3,840 feet) across uneven terrain and exploded, coming to rest in a gully, a top official of the investigative commission told a news conference in Madrid on Tuesday. Many of the bodies were badly charred from the fire, and authorities have used DNA samples to carry out numerous identifications.

What was the source of the error, and how was it resolved?

We were cornered in a sort of way already. But these butchers up the cavern had been surprised, they were probably scared, and they had no special weapons, only those little hatchets of theirs. And that way lay escape. Their sturdy little forms--ever so much shorter and thicker than the mooncalf herds--were scattered up the slope in a way that was eloquent of indecision. I had the moral advantage of a mad bull in a street. But for all that, there seemed a tremendous crowd of them. Very probably there was. Those Selenites down the cleft had certainly some infernally long spears. It might be they had other surprises for us.... But, confound it! if we charged up the cave we should let them up behind us, and if we didn't those little brutes up the cave would probably get reinforced. Heaven alone knew what tremendous engines of warfare--guns, bombs, terrestrial torpedoes--this unknown world below our feet, this vaster world of which we had only pricked the outer cuticle, might not presently send up to our destruction. It became clear the only thing to do was to charge! It became clearer as the legs of a number of fresh Selenites appeared running down the cavern towards us.
Where are the Selenites in relation to the narrator?