Answer:
Explanation:
Let the potential difference between the plate is V . Then in the first case
Electric field E between plate
E₁ = V / d
where d is separation between plate
When the plate separation becomes d / 2
Electric field E between plate
E₂ = V / d /2
= 2 V / d =2E₁
Or twice the earlier field
Answer:
b) the result we got can be termed approximation because we are neglecting the shear stress acting on the two ends of the cylinder. Here we have considered only the share stress acting on the curved surface area only.
Explanation:
check attachment for solution to A
Answer:
I believe it's frictional force
How much gravitational potential energy does the block have
when it gets to the top of the ramp ?
(weight) x (height) = (15 N) x (0.2 m) = 3 Joules .
If there were no friction, you would only need to do 3 Joules of work
to lift the block from the bottom to the top.
But the question says you actually have to do 4 Joules of work
to get the job done.
Friction stole one of your Joules along the way.
Choice-4 is not the correct one.
Choice-1 is the correct one.
===========================
Notice that the mass of the block is NOT 15 kg , and you
don't have to worry about gravity to answer this question.
The formula for potential energy is (m)·(g)·(h) .
But (m·g) is just the WEIGHT, and the formula
is actually (weight)·(height).
The question GIVES us the weight of the block . . . 15 N .
So the potential energy at the top is just (15N)·(0.2m) = 3 Joules.
Answer:
(a) average velocity = 17.6 m/s
(b) when t = 0, v = 0
when t = 4, v = 19.2 m/s
when t = 8, v = 28.8 m/s
(c) after starting from rest, the car will be at rest again in 20 s
Explanation:
Given;
x(t)=bt²−ct³, substitute the given values and the equation will become;
x(t)=3t²−0.1t³
(a)average velocity = total distance / total time
total distance, x(t) = 3t²−0.1t³
x(8) = 3t²−0.1t³
X(8) = 3(8)² - 0.1(8)³
X(8) = 140.8 m
total time = 8 s
average velocity = 140.8 / 8
average velocity = 17.6 m/s
(b) instantaneous velocity = dx / dt
dx / dt = 6t - 0.3t²
when t = 0
v = 0
when t = 4 s
v = 6(4) - 0.3(4²) = 19.2 m/s
when t = 8 s
v = 6(8) - 0.3(8²) = 28.8 m/s
(c) the velocity is zero at dx / dt = 0
6t - 0.3t² = 0
t(6 - 0.3t) = 0
t = 0 or 6 - 0.3t = 0
t = 0 or 0.3t = 6
t = 0 or t = 6 / 0.3
t= 0 or t = 20 s
After starting from rest, the car will be at rest again in 20 s
