Answer:
fr ’= ½ F
Explanation:
For this exercise we use the translational equilibrium equation, on the axis parallel to the wall
fr - W = 0
fr = W
for the adult man they indicate that the friction force is equal to F
F = M g
we write the equilibrium equation for the child
fr ’= w’
fr ’= m g
in the statement they tell us that the mass of the adult is 2 times the mass of the child
M = 2m
we substitute
fr ’= M / 2 g
fr ’= ½ Mg
we substitute
fr ’= ½ F
therefore the force of friction in the child is half of the friction in the adult
<span>the picture bellow gives you all the answers, this picture was given to my class by my science teacher a few years ago so it is accurate
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Answer:

Explanation:
Let the child is moving with speed same as the speed of water flow
So here the position of child with respect to flow must be zero
And if the boat start at an angle with the vertical
so its relative speed with flow of water is given as


now the time to reach the child is given as

so now we have

So the time to catch the child is given as


So distance moved by it in 0.104 h
distance moved by the boat in upstream direction given as


In y direction the displacement of boat is

net displacement of the ball is given as



Explanation:
It is given that, a long, straight wire is surrounded by a hollow metal cylinder whose axis coincides with that of the wire.
The charge per unit length of the wire is
and the net charge per unit length is
.
We know that there exist zero electric field inside the metal cylinder.
(a) Using Gauss's law to find the charge per unit length on the inner and outer surfaces of the cylinder. Let
are the charge per unit length on the inner and outer surfaces of the cylinder.
For inner surface,



For outer surface,



(b) Let E is the electric field outside the cylinder, a distance r from the axis. It is given by :


Hence, this is the required solution.
Mechanical advantage is defined as the ratio of output load to the input load. The mechanical advantage of the machine will be 0.1.
<h3>What is
mechanical advantage?</h3>
Mechanical advantage is a measure of the ratio of output force to input force in a system,
It is used to obtain the efficiency of forces in levers and pulleys. It is an effective way of amplifying the force in simple machines like levers.
The theoretical mechanical advantage is defined as the ratio of the force responsible for the useful work in the system to the applied force.
Given
applied force = 250 N
Output force = 25
Mechanical advantage = work output / work input



Hence the mechanical advantage of the machine will be 0.1
To learn more about the mechanical advantage refer to the link;
brainly.com/question/7638820