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:
<h2>36 km</h2>
Explanation:
The distance covered by an object given it's velocity and time taken can be found by using the formula
distance = velocity × time
From the question we have
distance = 18 × 2
We have the final answer as
<h3>36 km</h3>
Hope this helps you
Answer:
C
Sign-Negative
Explanation:
We are given that
Electric field =
(Radially downward)
Acceleration=
(Upward)
Mass of charge=3 g=
kg
1kg=1000g
We have to find the magnitude and sign of charge would have to be placed on a penny .
By newton's second law
Substitute the values then we get
Substitute the values then we get
C
Sign of charge =Negative
Because electric force acting in opposite direction of electric field therefore,charge on penny will be negative.
The answer is B. metalloids
(boron, silicon, germanium, arsenic, antimony, tellurium, astatine, and polonium)
Answer:
(a) 0
(b) 10ML
(c) 
(d) 
Explanation:
(a) When hanging straight down. The child is at the lowest position. His potential energy with respect to this point would also be 0.
(b) Since the rope has length L m. When the rope is horizontal, he is at L (m) high with respect to the lowest swinging position. His potential energy with respect to this point should be
where g = 10m/s2 is the gravitational acceleration.
(c) At angle 
from the vertical. Vertically speaking, the child should be at a distance of 
to the swinging point, and a vertical distance of 
to the lowest position. His potential energy to this point would be:
(d) at angle 
from the horizontal. Suppose he is higher than the horizontal line. This would mean he's at a vertical distance of 
from the swinging point and higher than it. Therefore his vertical distance to the lowest point is 
His potential energy to his point would be:
