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NRG3 homework help

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okay homework help with assignment nrg2 which is on page 262 if you textbook its problems 6 7 and 8 so start with problem 6 and airplane passenger is carries a 215 Newton so that's not kilograms that's Newton that's its weight incase up the stairs a displacement of 4.2 M vertically and 4.60 M horizontally so let's get a little drawing to this  so a staircase and there's a vertical displacement there's a horizontal displacement so this is my vertical is 4.20 meters  and this one is .60 meters  so once the person gets the suitcase moving to the right while they're going up the staircase the horizontal it's going to keep moving you don't need to do anything horizontally all the work that needs to be done needs to be done vertically to overcome the weight of his suitcase so let's start organizing a little bit here we know the weight of the suitcase is 215 Newtons  and that's the force we need to lift with if we're going to lift this thing so Go the Distance we're going to lift it is vertically the way that gravity Works its 4.20 meters so 4.2 m and let's see what you think about Theda now how much work does the passenger do or ask so a is the passenger so the passing Farm here is pulling up on the suitcase and a suitcase the arm pulls up the suitcases also moving up since their pull stop and it's moving up the angle for Theta is 0 degrees both of these are in the same direction pointing straight up so now here it's FD Coast Ada and I think you finish that one up  let's go to number 7  number seven a rope is used to pull a metal box a distance of 15 meters across the floor the Rope is held in an angle of 46 degrees with the floor and a force of 628 Newtons is applied to the Rope how much work does force on the Rope 2 Okay so let's maybe picture this one a rope a metal box the Rope is held an angle of 46 degrees with the floor so here we floor  and then we'll have a metal box  and there's a rope this is 46 degrees looks like a little less than 46 hour I drew it but we'll just say it's 46 degrees and this rope has a force of 628 Newtons along this line the object is going to move this way Dad it's moving 15 meters so let's organize some things here what I know is first I know the force 628 Newtons I know the displacement or distance it's moving is 15 meters and then last thing I need to find work is Theta so let's see that's the angle between the displacement vector and the force Vector so the angle between the force and the displacement so that's at 46 degrees so now I've deco's fada thank you can finish that one up  kids number 8 this one gets a little tricky a bicycle Rider pushes a bye go to has a mass of 13 kilograms up a steep hill the incline is 25 degrees and the road is 275 M long the writer pushes the bike peril the road with a force of 25 Newtons so so there the bicycle up the hill there not writing it so the bicycle has a mass of 13 kg so let's make a diagram here we have a bicycle and pushed Papa Hill this hill has an angle of 5 degrees with the horizontal so this is called the horizontal and it's being pushed by a person up the hill with 25 Newtons of force and it's moving up the hill 275 M long so let's see what I can organize here for part A Part hey is asking how much work does the rider do well some Rider pushing the bike so not really riding so the force that they're pushing the bike with is 225 Newton's the displacement is distance is 275 M beta know some people might go right here go there's an angle that must be it but I think the force is up the incline the right is moving up the incline so they're both in the same direction so they to hear is 0 degrees so now FD Coast Data thank you can finish a now let's go to be no BS is something different  how much work is done by the gravity on the bike so the force of gravity is also known as wait so wait that's our force that were looking at and this and we Force  can be found by an x g that's weight force in the bicycles moving this way up the incline which is 5 degrees to the horizontal and it's moving a displacement of 275 M now we're not using this 25 Newton Force because we're not being asked short is the person do we're being asked how much work does gravity do so gravity in this case let's organize now the force is the wait and that's going to be an x g here so Mass we're told is 13 kilograms 13 kg we know G on Earth is 9.8 m per second squared  and then what else do we know here we know the displacement is that same 207 5 meters up the incline the last thing as what's data  on this case draw a line right here this is 90 degrees so from here to here 90 and an additional 25 90 + 25 equals 115 degrees so Theta is 115 degrees don't be surprised when you do this problem if you get a negative answer because if it's going up the hill that means the work done by gravity is trying to slow down the subject so we should get a negative amount of work we can finish this one good luck

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