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
gogolik [260]
3 years ago
13

The 80.0-lb boy at a is suspended from the cable that passes over the quarter circular cliff rock. determine if it is possible f

or the 190-lb woman to hoist him up. the coefficient of static friction between the cable and the rock is μs = 0.2, and between the shoes of the woman and the ground μ′s= 0.8.
Physics
1 answer:
IrinaVladis [17]3 years ago
4 0
<span>Yes, it's possible to hoist the child up. Let's first determine the maximum amount of pull that the woman can exert. That will be the simple product of her weight and the coefficient of static friction with her shoes and the ground. So 0.8 * 190 = 152. So far, so good, since 152 is greater than the boy's 80 lbs. But the cable rubs at the cliff edge and that means that the lady has to pull harder. Let's see how much harder. There will be 80 lbs of tension on the cable, pressing against the cliff edge. So let's multiply by the coefficient of friction to get how much that is 0.2 * 80 = 16 So friction will take 16 lbs of effort to overcome. So the lady needs to pull with 80 + 16 = 96 lbs of force to move the boy. And since we've determined earlier that she can pull with up to 152 lbs of force, she can easily hoist the child up.</span>
You might be interested in
A basketball center holds a basketball straight out, 2.0 m above the floor, and releases it. It bounces off the floor and rises
atroni [7]

Answer:

a) The velocity of the ball before it hits the floor is -6.3 m/s

b) The velocity of the ball after it hits the floor is 3.1 m/s

c) The magnitude of the average acceleration is 470 m/s². The direction is upward at an angle of 90º with the ground.

Explanation:

First, let´s calcualte how much time it takes the ball to hit the floor:

The equation for the position of the ball is:

y = y0 + v0 * t + 1/2 g * t²

Where:

y = position at time t

y0 = initial position

v0 = initial velocity

t = time

g = acceleration due to gravity

We take the ground as the origin of the reference system.

a) Since the ball is realesed and not thrown, the initial velocity v0 is 0. The direction of the acceleration is downward, towards the origin, then "g" will be negative. When the ball hits the ground its position will be 0. Then:

0 = 2.0 m + 0 m/s *t - 1/2 * 9.8 m/s²  * t²

-2.0 m = -4.9 m/s²  * t²

t² = -2.0 m / - 4.9 m/s²

t = 0.64 s

The equation for the velocity of a falling object is:

v = v0 + g * t      where "v" is the velocity

since v0= 0:

v = g * t = -9.8 m/s² * 0.64 s = -6.3 m/s

b) Now, we know that the velocity of the ball when it reaches the max height must be 0. We can obtain the time it takes the ball to reach that height from the equation for velocity and then use that time in the equation for position to obtain the initial velocity:

v = v0 + g * t

0 = v0 + g * t

-v0/g = t

now we replace t in the equation for position, since we know that the maximum height is 1.5 m:

y = y0 + v0 * t + 1/2* g * t²           y = 1.5 m       y0 = 0 m   t = -v0/g

1.5 m = v0 * (-v0/g) + 1/2 * g (-v0/g)²

1.5 m = - v0²/g - 1/2 * v0²/g

1.5 m = -3/2 v0²/g

1.5 m * (-2/3) * g = v0²

1.5 m * (-2/3) * (-9.8 m/s²) = v0²

v0 = 3.1 m/s

c) The average acceleration will be:

a = final velocity - initial velocity / time

a = 3.1 m/s - (-6.3 m/s) / 0.02 s = 470 m/s²

the direction of the acceleration is upward perpendicular to the ground.

The vector average acceleration will be:

a = (0, 470 m/s²) or (470 m/s² * cos 90º, 470 m/s² * sin 90º)

4 0
2 years ago
Which type of electromagnetic radiation may damage central nervous system
Furkat [3]

Answer:

microwaves

Explanation:

microwaves do emit radiation, technically speaking, but it's not the DNA-damaging radiation we're used to hearing about. Microwaves, along with radio waves from (you guessed it) radio and cell phone towers, are types of non-ionizing radiation.

5 0
3 years ago
Read 2 more answers
An object is 39 cm away from a concave mirrors surface along the principles axis. If the mirrors focal length is 9.50 cm, how fa
Tatiana [17]

Answer:

12.6 cm

Explanation:

We can use the mirror equation to find the distance of the image from the mirror:

\frac{1}{f}=\frac{1}{p}+\frac{1}{q}

where here we have

f = 9.50 cm is the focal length

p = 39 cm is the distance of the object from the mirror

Solving the equation for q, we find:

\frac{1}{q}=\frac{1}{f}-\frac{1}{p}=\frac{1}{9.50 cm}-\frac{1}{39 cm}=0.080 cm^{-1}\\q = \frac{1}{0.080 cm}=12.6 cm

5 0
3 years ago
HELP I NEED THE ANSWER NOW
Setler79 [48]

Answer:

Speed of light

Explanation:

The famous Einstein's equation is:

E=mc^2

where

E is the energy

m is the mass

c=3\cdot 10^8 m/s is the speed of light

In this equation, Einstein summarized the following fact: mass can be converted into energy, and the amount of energy released in such a process is given by the equation.

An example of application of this equation is the nuclear fusion process. In a nuclear fusion, two lighter nuclei combine into a heavier nucleus. However, the mass of the heavier nucleus is slightly less than the sum of the masses of the two original nuclei: some of the mass of the original nuclei has been converted into energy, accorging to the previous equation.

4 0
3 years ago
“Force of impact”is:
Bumek [7]
In mechanics, an impact is a highforce or shock applied over a short time period when two or more bodies collide. Such a force or acceleration usually has a greater effect than a lower force applied over a proportionally longer period. ... Resilient materials will have betterimpact resistance.
4 0
3 years ago
Other questions:
  • 1. A soccer ball is kicked at ground level at 30 m/s at an angle of 53° to the horizontal.   a. How far away does it land? b. Ho
    11·1 answer
  • Can anyone help me for this question please?? I really need help someone!!!
    15·1 answer
  • A resistor and a capacitor are connected in series across an ideal battery having a constant voltage across its terminals. Long
    11·1 answer
  • With what minimum speed must you toss a 130 gg ball straight up to just touch the 15-mm-high roof of the gymnasium if you releas
    14·1 answer
  • How is a driver supposed to act?
    12·2 answers
  • Two enery converrsation that take place when you warm a cup of cocoa in a microwave<br> Oven
    13·1 answer
  • Which point refers to the epicenter of an earthquake?
    8·2 answers
  • During an off-day, Mike Trout, Shohei Ohtani, and Albert Pujols and having a pool party. They are tugging on a ring for some odd
    6·1 answer
  • What type of bond is formed when a metal from group 2 reacts with a nonmetal from group 6
    12·1 answer
  • ⦁ A certain resistor is required to dissipate 0.25 W, what standard rating should be used?
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!