Question

besides the gravitational force, a 2.80-kg object is subjected to one other constant force, the object starts from rest and in 1.20 s experiences a displacement of (4.20 i - 3.20 j) m. where the direction of j is the upward vertical direction. Determine the other force.

Answer 1

so what i think i should do...

Answer 2

i think i solve for acceleration first

\[a = \frac{2(4.20 \hat i - 3.20 \hat j )}{(1.20)^2}\]

Answer 3

\[a = \frac{2(4.20 i - 3.20 j)}{1.44}\]

Answer 4

so now i use \[\sum y = ma\]

Answer 5

K so i think that u need help now : http://answers.yahoo.com/question/index?qid=20080911200716AAYdMDE

please have a look if it does not help u then please tell

Answer 6

i mean \[\sum F_y = ma\]

Answer 7

@vishweshshrimali5

Answer 8

i dont understand that guy's notations o.O can you explain it to me simply :/

Answer 9

ouch ! it hurted me :D may be @vishweshshrimali5 help u

Answer 10

why was that you? lol

Answer 11

Hi @lgbasallote

What's the problem

Answer 12

if what im doing is right

Answer 13

How did u calculate the acc.

I mean by which formula

\[v^2 = u^2 + 2aS\]

Answer 14

is it a horizontal force?

Answer 15

Is this the formula u used?

Answer 16

i was doing \[F_1 - W = ma\]
\[F_1 - (2.8)(9.8) = 2.8 \times \frac{2(4.20 i -3.30j)}{1.44}\]

Answer 17

i used \[a = \frac{2d}{t^2}\]

Answer 18

is it a horizontal force?

Answer 19

i dont know...

Answer 20

doesnt seem to be

Answer 21

it has i and j

Answer 22

so is my solution right?

Answer 23

then we will have numerous answers as the force might also act in an angle,considering horizontal force as gravity corresponds to vertical displacement u can find the force acting which corresponds to 4.2m displacemnt in horizontal direction

Answer 24

im guessing the force is wherever the answer is simplest lol..im not a full-time physicist to determine infinite number of forces

Answer 25

if u simply do s=1/2gt^2 we get 7.2m so that corresponds to 3.2j in the vertical directio so wat does 3.2 correspond to?

Answer 26

1/2gt^2?

Answer 27

s=ut+1/2gt^2

Answer 28

oh g as i acceleration

Answer 29

that wud come to 9.45 so s=9.45 and then calculate a then F=ma and hence forcve in HORIZONTAL direction

Answer 30

wait tell me first...was i doing it right

Answer 31

no for dispalcement u cannot do 4.2-3.2 as they are in different directions

Answer 32

i didnt subtract them o.O

Answer 33

or u can do like this......resulatnt acceleeration isroot of a^2+g^2

Answer 34

then resultant displacement is root of 4.2 square +3.2square and then go for finding a

Answer 35

wait....was i doing it right a while ago???/

Answer 36

u undersatnd why i square and add and take square root as they are mutually perpendicular vectors

Answer 37

i wasnt finished yet anyway

Answer 38

u get it?

Answer 39

yes i do...what im asking is about my owrk

Answer 40

work*

Answer 41

no simple subtraction wont fewtch u answer u have to do it vectorially

Answer 42

i wasnt subtracting

Answer 43

it's like x - y i just put it there it's not yet finished

Answer 44

k go on and finally check ur answer with wat i told

Answer 45

\[F_1 = \frac{2(5.34)}{1.44} + 27.44\]
\[F_1 = \frac{10.68}{1.44} + 27.44\]
\[F_1 = 7.42 + 27.44\]
\[F_1 = 34.86 N\]

Answer 46

is that correct?

Answer 47

can u expalin ur steps?

Answer 48

what do you mean?

Answer 49

explain your steps?

Answer 50

i did nothing fancy...it was just algebra..what do you mean explain o.O