Let original length be L. The new length is therefore 4L.
Let original cross sectional surface area of the wire be equal to πr^2.
This means original volume was L x πr^2 = Lπr^2
The volume is the same but the length is different so 4L x new surface area must be equal to Lπr^2. Let new surface area be equal to Y.
4L x Y = Lπr^2
=> Y = (πr^2 )/ 4
Using the resistivity formula,
R = pL/A. p which is resistivity is a constant so it stays the same
But this time, instead of L we have 4L and instead of πr^2 we have (πr^2)/4.
so the new resistance
= (4Lp)/ {(πr^2)/4}
= 16 (pL)/(πr^2)
= 16 (pL)/A. because πr^2 is A
since pL/A is equal to R from the formula, this is equal to
16 R.
R was 10 ohms
therefore new resistance is 16 x 10 = 160 ohms
Answer:
15%
Explanation:
Step one:
Given data
Energy source= 300J
Useful energy = 45J
Waste energy = 255J
Required
The efficiency of the solar system
Step two:
The efficiency is computed by factoring only the useful work and the energy source
Efficiency= 45/300*100
Efficiency= 0.15*100
Efficiency= 15%
Answer:
Because Jupiter is a much larger planet than Earth, its gravitational pull is 240% stronger than that of earth. This is why sawdust, which is lighter than its equivalent measure of sugar would weigh more on Jupiter.
Explanation:
Let's assume that a type of bag can contain 50 kilograms of sugar. If that same bag was filled up with sawdust instead, it would weigh far less than 50Kg.
If that bag of sawdust, on earth weighed 35Kg for instance, on Jupiter, the new weight would be:
35Kg x 2.4 = 84Kg
Put differently, Jupiter simply has a stronger gravitational pull than earth. This extra pull is attributed to its size.
Cheers
Answer and Explanation:
a. An oxygen-filled balloon is not able to float in the air, because the oxygen inside the balloon is of the same density, that is, the same "weight" as the oxygen outside the balloon and present in the atmosphere. The balloon can only float if the gas inside it is less dense than atmospheric oxygen. Helium gas is less dense than atmospheric gas, so if a balloon is filled with helium gas, that balloon will be able to float because of the difference in density.
b. The ship is able to float in the water because its steel construction is hollow and full of air. This makes the average density of this ship less than the density of water, which makes the ship lighter than water and for this reason, this ship is able to float. In addition, the ship is partially immersed, allowing the weight of the ship on the water to counteract the buoyant force that the water promotes on the ship. Weight and buoyant are two opposing forces that keep the ship afloat.
