How much rope would need to be pulled through a pulley with a mechanical advantage of 2 to lift a load 4 ft?
2 answers:
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Answer:
32 km east
Explanation:
In order to find the final position of the balloon, we need to calculate its total displacement.
We have:
- Displacement towards west: 18 km
- Displacement towards east: 50 km
The two vectors are on the same line: this means that we can simply add them together (taking into account the proper direction) to obtain the total displacement.
Taking east as positive direction and west as negative direction, we have:
And since it is positive, it means that the final position of the balloon is 32 km east from its initial position.
Answer:
The percentage change in resistance of the wire is 69%.
Explanation:
Resistance of a wire can be determined by,
R = (ρl) ÷ A
Where R is its resistance, l is the length of the wire, A its cross sectional area and ρ its resistivity.
When the wire is stretched, its length and area changes but its volume and resistivity remains constant.
= 1.3l, and
=
So that;
= (ρ
) ÷
= (ρ × 1.3l) ÷ (
)
= (1.3lρ) ÷ ()
= × [(ρl) ÷ A]
= 1.69R (∵ R = (ρl) ÷ A)
= 1.69R
Where is the new resistance,
is the new length, and
is the new area after stretching the wire.
The change in resistance of the wire = - R
= 1.69R - 1R
= 0.69R
The percentage change in resistance = × 100
= 0.69 × 100
= 69%
The percentage change in resistance of the wire is 69%.