- #1

ant284

Hi,

here is the question:

there is a elevator, an man is in it, via a pulley he can raise the elevator.

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zzzzz|zz\

zzzzz|zz|

---zz|------

|zzzz|zzzzz|

|zzzz|zzzzz|

|zzz\o/zzzz|

|zzzz|zzzzz|

|zzz/z\zzzz|

------------

This is my picture so can't do better

z are empty space as this forums gets rid of them

there is a man in the middle of the box, pulling a pulley.

the elevator is 30kg the man is 70kg,

this man exert a force of 300N to rise himself, we need to find the acceleration.

the answer is 5m/s^2 but i can't find why.

What i do is that

the mass of the whole system is 100kg (man + elevator)

the tension in the string is 300N, and using the formula

Mg-T=ma

where g = 10

700-300=100a

4m/s^2

any feed back is appreciated

here is the question:

there is a elevator, an man is in it, via a pulley he can raise the elevator.

zzzzz/o\

zzzzz|zz\

zzzzz|zz|

---zz|------

|zzzz|zzzzz|

|zzzz|zzzzz|

|zzz\o/zzzz|

|zzzz|zzzzz|

|zzz/z\zzzz|

------------

This is my picture so can't do better

z are empty space as this forums gets rid of them

there is a man in the middle of the box, pulling a pulley.

the elevator is 30kg the man is 70kg,

this man exert a force of 300N to rise himself, we need to find the acceleration.

the answer is 5m/s^2 but i can't find why.

What i do is that

the mass of the whole system is 100kg (man + elevator)

the tension in the string is 300N, and using the formula

Mg-T=ma

where g = 10

700-300=100a

4m/s^2

any feed back is appreciated

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