A boat heads north at 30 mph while a steamer heads east at 40 mph at the same time. When is the distance between them 50 mi? Ans
1 answer:
Answer:
1 hour
Explanation:
Speed of the first boat = 30 mph
Speed of the second = 40 mph
The boats will cover different distances but the time taken will be the same.
Time taken by the boats = t
Distance = Speed × Time
Distance covered by the first boat = 30t
Distance covered by the second boat = 40t
Distance between the boats = 50 mi
From the Pythagoras theorem
Time taken by the boats when they are 50 mi away is 1 hour
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Answer:
λ = a
Explanation:
This is a diffraction exercise that is described by the expression
a sin θ = m λ
sin θ = m λ/ a
the first zero of the diffraction occurs for m = 1
sin θ = λ / a
angles are generally very small and are measured in radians
sin θ = θ = y / x
we substitute
the width of the central maximum is twice the distance to zero
w = 2y
in the exercise indicate that this width is equal to twice the distance to the screen (2x)
W = 2x
2y = 2x
we substitute
1 = λ/ a
λ = a
we see that the width of the slit is equal to the wavelength used.