Question

Momentum/Energy Problems (ONE QUESTION UNSOLVED IN COMMENTS)

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[49] You and a friend each carry identical boxes to a room one floor above you and down the hall. You choose to carry it first up the stairs, then down the hall. Your friend carries it down the hall, then up another stairwell.
Who does more work?

[52] An airplane passenger carries a 215 N suitcase up stairs, a displacement of 4.20 m vertically and 4.60 m horizontally.
a) How much does the passenger do?
b) The same passenger carries the same suitcase back down the same stairs. How much work does the passenger do now (I know this is the negative of the original answer in part A)?

In #52 the answer for A is given as 903 J, but I got 1333 or 1339 J (first one is rounded up)...

Answer 1

[49] I think both consumes the same energy. As PE at the end gets equalled.

Answer 2

[52] We have to find Potential Energy (PE)
PE = m* g * h ---------------> (m*g = weight = 215 N)
= 215 * 4.2
= 903 J

Answer 3

Alright, thanks @veeramanikandan! :)

Answer 4

[54] A worker pushes a crate weighing 93 N up an inclined plane, pushing horizontally, parallel to the ground.
a) The worker exerts a force of 85 N. How much work does he do? // ANSWER GIVEN: 340 J
b) How much work is done by gravity? // ANSWER GIVEN: -279 J

Answer 5

I can't answer the last question because there is no distance given... D;

Answer 6

you are missing out the angle of inclination or the dimentions of the inclined plane

Answer 7

the diagram shd look something like this

Answer 8

Yeah @ememlove but they don't give anything else so I'm stuck :[

Answer 9

thats really weird there's no diagram at all? they must give the dimension or else we cannot solve this

Answer 10

exactly I have to have more info @ememlove :[

Answer 11

the height and the length are given.. :). .

Answer 12

where @Mashy ?

Answer 13

"a displacement of 4.20 m vertically and 4.60 m horizontally".

Answer 14

I'm talking about [54] @Mashy :/