A train travels 90 kilometers in 4 hours, and then 82 kilometers in 1 hours. What is its average speed?
1 answer:
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Answer:
2.47 m
Explanation:
Let's calculate first the time it takes for the ball to cover the horizontal distance that separates the starting point from the crossbar of d = 52 m.
The horizontal velocity of the ball is constant:
and the time taken to cover the horizontal distance d is
So this is the time the ball takes to reach the horizontal position of the crossbar.
The vertical position of the ball at time t is given by
where
is the initial vertical velocity
g = 9.8 m/s^2 is the acceleration of gravity
And substituting t = 2.56 s, we find the vertical position of the ball when it is above the crossbar:
The height of the crossbar is h = 3.05 m, so the ball passes
above the crossbar.
Answer:
a
b
c
Explanation:
From the question we are told that
The angle of incidence is
The refractive index of water is
Generally Snell's law is mathematically represented as
Here is the refractive index of air with value
is the angle of refraction
So
=>
=>
Given that the angle should not be greater than then the angle of incidence will be
=>
=>
Generally for critical angle is mathematically represented as
=>
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