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
The answer is B tell me if I am wrong.
The acceleration of the car is 0.8049
.It takes 13.802s to travel the 230 m.
<h3>
What is acceleration?</h3>
In mechanics, acceleration refers to the rate at which an object's velocity with respect to time varies. Acceleration is a vector quantity (in that they have magnitude and direction). The direction of an object's acceleration is determined by the direction of the net force acting on it. Newton's Second Law states that the combined effect of two factors determines how much an item accelerates:
(i) It follows that the magnitude of the net balance of all external forces acting on the object is directly proportional to the magnitude of this net resulting force, and
(ii) the mass of the thing, depending on the materials out of which it is constructed, is inversely proportional to the mass of the thing.
Calculations:
40 km/hr ----- 11.11m/s
80 km/hr ----- 22.22m/s
Time taken
v-u=at
22.22-11.11= 0.8049 x t
t=13.802s
To learn more about acceleration ,visit:
brainly.com/question/2303856
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Answer:
No, not at all. This kinetic energy of car is converted/lost in the form of sound and heat under the tyre when driver apply brakes.
Explanation:
This law states that energy can neither be created nor destroyed but it changes from one form to the other.
In this case reduction of kinetic energy of car does not contradict the law but it changes into heat and sound energy. When driver apply brakes we hear the sound of Tyre due to friction with the road. The tyre become hot too.
So it is not in contradiction to the law of conservation of energy (First Law of Thermodynamics).
Please mark branliest if you are satisfied with the answer. Thanking you in anticipation.
30 m/s because that is the form that suppose to be for velocity
