1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Alenkinab [10]
3 years ago
12

A 15.0-m uniform ladder weighing 500 N rests against a frictionless wall. The ladder makes a 60.08 angle with the horizontal. (a

) Find the horizontal and vertical forces the ground exerts on the base of the ladder when an 800-N firefighter has climbed 4.00 m along the ladder from the bottom. (b) If the ladder is just on the verge of slipping when the firefighter is 9.00 m from the bottom, what is the coefficient of static friction between ladder and ground
Physics
1 answer:
grigory [225]3 years ago
7 0

Answer:

a)  fr = 266.92 N,   fy = 1300 N,  b)    μ = 0.36

Explanation:

a) This is a balancing act.

Let's write the rotational equilibrium relations, where the turning point is the bottom of the ladder and the counterclockwise rotations are positive

             -w x - W x₂ + R y = 0         (1)

usemso trigonometry to find distances

            cos 60.08 = x / 7.5

            x = 7.5 cos 60.08

            x = 3.74 m

fireman

           cos 60.08 = x₂ / 4

           x2 = 4 cos 60

           x2 = 2 m

wall support

           sin 60.08 = y / 15

           y = 15 are 60.08

           y = 13 m

we substitute in equation 1

           R y = w x + W x2

            R = (w x + W x2) / y

            R = (500 3.74 +800 2) / 13

            R = 266.92 N

now let's write the expressions for the translational equilibrium

X axis

           R -fr = 0

           R = fr

           fr = 266.92 N

Y Axis  

           Fy - w-W = 0

           fy = 500 + 800

           fy = 1300 N

b) ask the friction coefficient

the firefighter's distance is

          cos 60.08 = x₃ / 9.00

          x₃ = 9 cos 60

          x₃ = 5.28 m

from equation 1

          R = (w x + W x₃) / y

          R = 500 3.74 + 800 5.28) / 13

          R = 468.769 N

we saw that

          fr = R = 468.769

The expression for the friction force is

          fr = μ N

in this case the normal is the ratio to pesos

        N = Fy

       N = 1300 N

        μ N = fr

        μ = fr / N

        μ = 468,769 / 1300

         μ = 0.36

You might be interested in
in a certain experiment, a radio transmitter emits sinusoidal electromagnetic waves of frequency 105.0 mhz in opposite direction
Romashka [77]

As a result, the hollow is 10.90 meters long and the distance between the nodal planes is 1.36 meters.

<h3>Explain electromagnetic waves.</h3>

The oscillations between an electric field and a magnetic field produce waves known as electromagnetic waves, or EM waves.

By definition, we understand that the frequency equals,

f = c/λ

where,

λ = wavelength

c= Speed of light

λ = 2L / n

While the wavelength is equal to,

Where,

L = Length

n = Number of antinodes/nodes

PART A) We know that the first component's wavelength is 110 MHz, so

λ = c/ f

λ = 3*10^8 / 11*10^6

λ = 1.36m

Therefore the distance between the nodal planes is 1.36m

PART B) For this part we need to find the Length through the number of nodes (8) and the wavelength, that is,

λ` = 2l /n

L = 8*2.72/ 2

L = 10.90m

Therefore the length of the cavity is 10.90m.

To know more about electromagnetic waves visit:-

brainly.com/question/3101711

#SPJ4

7 0
1 year ago
Which statement explains the similarity between momentum and kinetic energy of an object?
Anon25 [30]

Answer:B.

Both increase as the mass and velocity increase.

3 0
3 years ago
Read 2 more answers
Which one of these exercises gets your heart pumping? *
Nookie1986 [14]

Answer:

swimming

Explanation:

5 0
2 years ago
Read 2 more answers
A 5-kg concrete block is lowered with a downward acceleration of 2.8 m/s2 by means of a rope. The force of the block on the Eart
maksim [4K]

When the body touches the ground two types of Forces will be generated. The Force product of the weight and the Normal Force. This is basically explained in Newton's third law in which we have that for every action there must also be a reaction. If the Force of the weight is pointing towards the earth, the reaction Force of the block will be opposite, that is, upwards and will be equivalent to its weight:

F = mg

Where,

m = mass

g = Gravitational acceleration

F = 5*9.8

F = 49N

Therefore the correct answer is E.

5 0
3 years ago
Humans must depend on the environment for their survival.<br> True<br> False
Alisiya [41]

Answer:

true

Explanation:

with out trees we would have no air with out animals the envirounment would slowly decay

8 0
3 years ago
Read 2 more answers
Other questions:
  • Two cars are heading towards one another . Car a is moving with an acceleration of 11. And carb is moving at -4 m/s^2. The cars
    15·1 answer
  • Here are the positions at three different times for a bee in flight (a bee's top speed is about 7 m/s). Time 6.6 s 6.9 s 7.2 s P
    9·1 answer
  • Galileo started modern science because he started using ? Rather than speculation
    12·1 answer
  • Please help me answer this question! Will appreciate help very much. a) Draw a circuit to show 3 lights in series b) Draw a circ
    7·1 answer
  • Is a roller coaster moving downhill is a potential or kinetic energy?
    7·1 answer
  • Please help me:(<br> I need help with this question
    12·1 answer
  • A car goes North a distance of 120 kilometers during a time period of 3.0 hours. What is the average
    13·1 answer
  • What contributions did J.J. Thomson make to atomic history?
    15·1 answer
  • Objects fall near the surface of the earth with a constant downward acceleration of 10 m/s2 . Suppose a falling object is moving
    15·1 answer
  • Which statements describe the principles of the big bang theory? Select two options. The universe is continuing to expand. The u
    13·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!