Answer:
The minimum force the climber must exert is about 439N.
Explanation:
We use the relationship between friction and normal force to answer this question:
We are given the static coefficients of friction but need to determine the friction force. To do that we consider the totality of forces acting on this hapless gentleman stuck in a chimney. There is the gravity acting downward (+), then there are two friction forces acting upward (-), namely through his shoes and his back. The horizontal force exerted by the climber on both walls of the chimney is the same and is met with equally opposing normal force. Since the climber is not falling the net force in the vertical direction is zero:
The normal force in this equilibrium is about 439N and because we are told that the static friction forces are both at their maximum, this value is at the same time the <em>minimum</em> force needed for the climber to avoid starting slipping down the chimney.
To solve this problem we can use the concepts related to the change of flow of a fluid within a tube, which is without a rubuleous movement and therefore has a laminar fluid.
It is sometimes called Poiseuille’s law for laminar flow, or simply Poiseuille’s law.
The mathematical equation that expresses this concept is
Where
P = Pressure at each point
r = Radius
Viscosity
l = Length
Of all these variables we have so much that the change in pressure and viscosity remains constant so the ratio between the two flows would be
From the problem two terms are given
Replacing we have to
Therefore the ratio of the flow rate through capillary tubes A and B is 1/32
Answer:
2 atoms of oxygen in carbon dioxide
Explanation:
Answer:
Given the point of maximun electric power of the hair dryer 1500 (w); The circuit breaker won´t trip at all
Explanation:
The most simplyfied relation between power, voltage and current is:
Electric power (in watts) =Voltage (in volts) * current (in ampers)
In the case of P= 1500 (w) and V= 120 (v) we have:
I = 1500/120 (a) = 12,65 (a)
This value is far away of 20 (a) (the nominal trip current
The answers to question 4 d
