Let F = the downstream speed of the water.
<span>Then the boat's upstream speed is: 15 - F </span>
<span>The boat's downstream speed is: 15 + F </span>
<span>Assume both the journeys mentioned take T hours, then using "speed x time = distance" we get: </span>
<span>Downstream journey: (15 + F)T = 140 </span>
<span>Upstream journey: (15 - F)T = 35 </span>
<span>Add the two formulae together: </span>
<span>(15 + F)T + (15 - F)T = 140 + 35 </span>
<span>15T + FT + 15T - FT = 175 </span>
<span>30T = 175 </span>
<span>T = 35/6 </span>
<span>Use one of the equations to find F: </span>
<span>(15 + F)T = 140 </span>
<span>15 + F = 140/T </span>
<span>F = 140/T - 15 </span>
<span>F = 140/(35/6) - 15 </span>
<span>F = 24 - 15 </span>
<span>F = 9 </span>
<span>i.e. the downstream speed of the water is 9 kph </span>
<span>Therefore, the boat's speed downstream is 15 + F = 15 + 9 = 24 kph.
the answer is: *24kph*</span>
Explanation:
Work is the dot product of the force and displacement vectors.
W = F · d
In other words, it is the force times the parallel component of the distance.
W = F d cos θ, where θ is the angle between the force and distance.
3.4m/s
Explanation:
Given parameters:
Distance to school = 14.4km
Time taken by Amy = 49min
Time taken by bill = 20min after Amy = 20+49 = 69min
Unknown parameters:
How much faster is Amy's average speed = ?
Solution:
Average speed is the rate of change of total distance with total time taken.
Average speed = 
convert units to meters and seconds
1000m = 1km
60s = 1min
Distance to school = 14.4 x 1000 = 14400m
Time taken by Amy = 49 x 60 = 2940s
Time taken by Bill = 69 x 60 = 4140s
Average speed of Amy = 
= 4.9m/s
Average speed of Bill = 
= 1.4m/s
Differences in speed = 4.9 - 1.5 = 3.4m/s
Amy was 3.4m/s faster than Bill
learn more:
Average speed brainly.com/question/8893949
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Maybe you can divide the volts its twelve if you do that but itll show you how much to double it by
Answer:
the intensity of the light after passing through the two polarizing filters is 4.11 units
Explanation:
Given the data in the question;
the intensity of an unpolarized light; I₀ = 25.0 units
when the unpolarized light passes through the first polarizer, its intensity reduces to half of its initial value;
⇒ I₁ = I₀/2 = 25/2 = 12.5 units
the angle between the transmission axes of two polarizers is;
∅ = 55° - 0° = 55°
The intensity of the light after passing through two polarizing filters will be;
I₂ = I₁cos²∅
we substitute
I₂ = 12.5 × cos²(55)
I₂ = 12.5 × 0.3289899
I₂ = 4.11 units
Therefore, the intensity of the light after passing through the two polarizing filters is 4.11 units
