Answer:
3.7 km/h
Explanation:
Let's call v the proper speed of the boat and v' the speed of the water in the river.
When the boat travels in the direction of the current, the speed of the boat is:
v + v'
And it covers 50 km in 3 h, so we can write
(1)
When the boat travels in the opposite direction, the speed of the boat is
v - v'
And it covers 50 km in 5.4 h, so
(2)
So we have a system of two equations: by solving them simultaneously, we find the value of v and v':
![v+v'=16.7 \\v-v'=9.3](https://tex.z-dn.net/?f=v%2Bv%27%3D16.7%20%5C%5Cv-v%27%3D9.3)
Subtracting the second equation from the first one we get:
![(v+v')-(v-v')=16.7-9.3\\2v'=7.4\\v'=3.7](https://tex.z-dn.net/?f=%28v%2Bv%27%29-%28v-v%27%29%3D16.7-9.3%5C%5C2v%27%3D7.4%5C%5Cv%27%3D3.7)
So, the speed of the water is 3.7 km/h.
1. No they aren’t because they all belong to different sports and are used differently
Answer:
100 cc
Explanation:
Heat released in cooling human body by t degree
= mass of the body x specific heat of the body x t
Substituting the data given
Heat released by the body
= 70 x 3480 x 1
= 243600 J
Mass of water to be evaporated
= 243600 / latent heat of vaporization of water
= 243600 / 2420000
= .1 kg
= 100 g
volume of water
= mass / density
= 100 / 1
100 cc
1 / 10 litres.
Answer:
80 angle of incidence=angle of reflection
Explanation:
The step of this scientific method is "draw conclusion".
<h3>What is scientific method?</h3>
The scientific method is the process of objectively establishing facts through testing and experimentation.
The basic scientific process or scientific method involves the following;
- making an observation
- forming a hypothesis
- making a prediction
- conducting an experiment
- analyzing the results and
- drawing conclusion.
Thus, if Kim’s experiment showed that chicken eggshells were stronger when she gave the hen feed, to which extra calcium had been added. The step of this scientific method is "draw conclusion".
Learn more about scientific method here: brainly.com/question/17216882
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