Answer:
h >5/2r
Explanation:
This problem involves the application of the concepts of force and the work-energy theorem.
The roller coaster undergoes circular motion when going round the loop. For the rider to stay in contact with the cart at all times, the roller coaster must be moving with a minimum velocity v such that at the top the rider is in a uniform circular motion and does not fall out of the cart. The rider moves around the circle with an acceleration a = v²/r. Where r = radius of the circle.
Vertically two forces are acting on the rider, the weight and normal force of the cart on the rider. The normal force and weight are acting downwards at the top. For the rider not to fall out of the cart at the top, the normal force on the rider must be zero. This brings in a design requirement for the roller coaster to move at a minimum speed such that the cart exerts no force on the rider. This speed occurs when the normal force acting on the rider is zero (only the weight of the rider is acting on the rider)
So from newton's second law of motion,
W – N = mv²/r
N = normal force = 0
W = mg
mg = ma = mv²/r
mg = mv²/r
v²= rg
v = √(rg)
The roller coaster starts from height h. Its potential energy changes as it travels on its course. The potential energy decreases from a value mgh at the height h to mg×2r at the top of the loop. No other force is acting on the roller coaster except the force of gravity which is a conservative force so, energy is conserved. Because energy is conserved the total change in the potential energy of the rider must be at least equal to or greater than the kinetic energy of the rider at the top of the loop
So
ΔPE = ΔKE = 1/2mv²
The height at the roller coaster starts is usually higher than the top of the loop by design. So
ΔPE =mgh - mg×2r = mg(h – 2r)
2r is the vertical distance from the base of the loop to the top of the loop, basically the diameter of the loop.
In order for the roller coaster to move smoothly and not come to a halt at the top of the loop, the ΔPE must be greater than the ΔKE at the top.
So ΔPE > ΔKE at the top. The extra energy moves the rider the loop from the top.
ΔPE > ΔKE
mg(h–2r) > 1/2mv²
g(h–2r) > 1/2(√(rg))²
g(h–2r) > 1/2×rg
h–2r > 1/2×r
h > 2r + 1/2r
h > 5/2r
Yes, electromagnetic can travel without medium.
Mechanical waves and electromagnetic waves are two important ways that energy is transported in the world around us.
Waves in water and sound waves in air are two examples of mechanical waves.
Mechanical waves are caused by a disturbance or vibration in matter, whether solid, gas, liquid, or plasma.
Matter that waves are traveling through is called a medium.
These mechanical waves travel through a medium by causing the molecules to bump into each other, like falling dominoes transferring energy from one to the next.
Sound waves cannot travel in the vacuum of space because there is no medium to transmit these mechanical waves.
On the other hand electromagnetic waves don't require medium for its propagation.
An easy example would be light which is an EM wave reaches earth even though space has no medium.
Learn more about different types of waves here:
brainly.com/question/13364787
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Answer:
B) 
Explanation:
The electric force between charges can be determined by;
F = 
Where: F is the force, k is the Coulomb's constant, 
is the value of the first charge, 
is the value of the second charge, r is the distance between the centers of the charges.
Let the original charge be represented by q, so that;
= 2q
= 
So that,
F = x 
= 2q x x
= 
x
= x 
F = x
The electric force between the given charges would change by .
The answer is B - Current Y has a greater potential difference, and the charges flow at a slower rate.
I just took the quiz
Answer:
1) Half Girlfriend
2) I am Malala
3) Diamond fire
4)I too had a love story
5)Your Dream are Now Mine
Explanation:
I don't have a same pattern to read but mostly of romantic and fiction. I read less autobiographies but when I read I am Malala , it was an inspiring one.My favorite type of reading is romantic types and least favorite is non fiction especially History
