The average velocity of a car that travels 450 km north in 9.0 h is 5.0 x 10 km/h
Answer:
v = 3.04 m/s
Explanation:
given,
mass of the block, M = 6.6 Kg
horizontal force, F = 12.2 N
distance, L = 2.5 m
initial speed = 0 m/s
speed of the block,v = ?
we now
Work done is equal to change in Kinetic energy.
Work done = Force x displacement
W = Δ K E
Δ K E = Force x displacement


3.3 v² = 30.5
v² = 9.242
v = 3.04 m/s
speed of the block is equal to 3.04 m/s
Answer:
h = 2.5 m
Explanation:
Given that,
Mass of a ball, m = 1.5 kg
Initial velocity of the ball, u = 7 m/s
We need to find the maximum height reached by the ball. Let it is be h. Using the conservation of energy to find it such that,

Put all the values,

So, it will reach to a height of 2.5 m.
Explanation:
Suppose you want to shine a flashlight beam down a long, straight hallway. Just point the beam straight down the hallway -- light travels in straight lines, so it is no problem. What if the hallway has a bend in it? You could place a mirror at the bend to reflect the light beam around the corner. What if the hallway is very winding with multiple bends? You might line the walls with mirrors and angle the beam so that it bounces from side-to-side all along the hallway. This is exactly what happens in an optical fiber.
The light in a fiber-optic cable travels through the core (hallway) by constantly bouncing from the cladding (mirror-lined walls), a principle called total internal reflection. Because the cladding does not absorb any light from the core, the light wave can travel great distances.
However, some of the light signal degrades within the fiber, mostly due to impurities in the glass. The extent that the signal degrades depends on the purity of the glass and the wavelength of the transmitted light (for example, 850 nm = 60 to 75 percent/km; 1,300 nm = 50 to 60 percent/km; 1,550 nm is greater than 50 percent/km). Some premium optical fibers show much less signal degradation -- less than 10 percent/km at 1,550 nm.
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