Answer:
2.83km/hr
Explanation:
Let stream flowing at the rat x km/hr
In still water
Speed of boat=4km/hr
Upstream speed=4-x
Downstream speed=4+x
Total time=2 hr
Time=Distance/speed
According to question
[tex]\frac{2}{4+x}+\frac{2}{4-x}=2[/tex]
[tex]\frac{8-2x+8+2x}{(4+x)(4-x)}=2[/tex]
[tex]\frac{16}{4^2-x^2}=2[/tex]
Using the formula
[tex](a+b)(a-b)=a^2-b^2[/tex]
[tex]4^2-x^2=\frac{16}{2}[/tex]
[tex]16-x^2=8[/tex]
[tex]16-8=x^2[/tex]
[tex]8=x^2[/tex]
[tex]x=\sqrt{8}=2.83km/hr[/tex]
Hence, the stream is flowing at 2.83km/hr
From base camp, a park ranger drives 27 meters at 32 degrees East of North, then 40 meters at 58 degrees West of North, and finally 39 meters directly West in an attempt to rescue a lost hiker.
Answer:
R = 73.34 m, θ = 37º North of West
Explanation:
In this exercise you are asked to find the distance traveled.
The best way to do this is with a Cartesian coordinate system, let's use a system where the x axis coincides with the West - East direction), to decompose the trajectories
First trajectory
distance d₁ = 27 m
Direction 32 East of North, this angle is measured from the vertical direction (y-axis)
cos 32 = y₁ / d₁
sin 32 = x₁ / d₁
y₁ = d₁ cos 32
x₁ = d₁ sin 32
y₁ = 27 cos 32 = 22.90 m
x₁ = 27 sin 32 = 14.31 m
second trajectories
distance d2 = 40 m
direction 58 West from North, the angle is measured with respect to the y axis, towards the negative side of the x axis
cos 58 = y₂ / d₂
sin 32 = x₂ / d₂
y₂ = d₂ cos58
x₂ = d₂ sin 58
y₂ = 40 cos 58 = 21.20 m
x₂ = 40 sin 58 = -33.92 m
The negative sign of the x coordinate is due to the fact that the displacement is towards the West (negative of the x axis)
third trajectory
distance d₃ = 39 m
West direction, negative part of x-axis
x₃ = - 39 m
the total distance is
= x₁ + x₂ + x₃
X_{total}l = 14.30 - 33.92 -39
X_{total}X_total = -58.6 m
Y_{total} = y₁ + y₂
Y_{total}= 22.90 + 21.20
Y_{total} = 44.1 m
we give the result in the form of module and angle
we use the Pythagorean theorem
R = [tex]\sqrt{X_{total}^2 + Y_{total}^2 }[/tex]
R =\sqrt58.6^2 + 44.1^2 }
R = 73.34 m
we use trigonometry
tan θ =
θ = tan⁻¹ \frac{ Y_{total} }{ X_{total} }
θ = tan⁻¹ \frac{ 44.1 }{ 58.6 } (44.1 / 58.6)
θ = -37º
this angle is in the second quadrant, given in the form of cardinal coordinates is
θ = 37º North of West
2. A car with mass 2,500 kg is travelling at 15 m/s. What is the car's kinetic energy?
a. 37,500 J
b. 563,000 J
c. 280,000 J
d. 350,000 J
Answer:
c, 280,000J
Explanation:
You should use the equation KE (Kinetic Energy) = [tex]\frac{1}{2} mv^2[/tex]
m = 2500
v = 15
KE = [tex]\frac{1}{2} * 2500 * (15)^2\\[/tex]
KE = 281250 Joules.
This is consistent with the answer B, as all of the parameters given to you are rounded to 2 significant figures so naturally, the answer should also be rounded to 2 sig figs.
KE = 280,000 J
3. Why is static electricity not useful as a power
source?
A. Because electrons aren't transferred in bursts of
static electricity
B. Because all energy is released at once in static
electricity
C. Because static electricity is not a real form of
electricity
D. Because static electricity only occurs in lightning
Static electricity is not useful as a power source primarily because it releases all of its energy at once rather than providing a continuous and controlled flow of electrical energy. The correct answer is B.
When static electricity is discharged, such as in a spark or a sudden discharge of stored charge, it happens in a rapid and uncontrolled manner, resulting in a brief burst of energy rather than a steady and sustained flow.
Power sources typically require a continuous and controllable flow of electrical energy to be useful for various applications. Static electricity, in its nature, does not provide this continuous flow but instead releases energy in an instantaneous manner. Therefore, it is not suitable for most practical power needs and applications.
Option A is not correct because electrons can be transferred in bursts of static electricity. Option C is not correct because static electricity is a real form of electricity, even though it has unique characteristics. Option D is not correct because static electricity can occur in various circumstances, not just in lightning.
Therefore, Static electricity is not useful as a power source primarily because it releases all of its energy at once rather than providing a continuous and controlled flow of electrical energy. The correct answer is B.
To know more about static electricity:
https://brainly.com/question/30043326?referrer=searchResults
#SPJ6
What part of the eye protects your eye from scratches?
retina
pupil
cornea
iris
Answer:
Cornea
Explanation:
The outer layer of the cornea is covered by epithelial cells that protect the surface. A corneal abrasion may result from dragging a piece of debris across the surface and scraping off the epithelial cells.
A book is sitting on the dashboard of a car that is stopped at a traffic light as the car starts to move forward the book slides backward off the dashboard what does the book actually do
Answer:
The book remained in its state of rest before the car started to move forward as no direct force acted on it.
Explanation:
According to Newton's first law of motion, a body will continue in its present state of rest, or if it is in motion, will continue to move with uniform speed in a straight line unless aced upon by an external force. This tendency of a body to remain in its state of reset or uniform motion in a straight line is known as inertia and is directly proportional to the mass of the body. The more massive a body, the more inertia it possesses. Thus Newton's first law is also known as the law of inertia.
Considering the case of the book on the dashboard of a stationary car which suddenly starts to move. While the car is stopped at the traffic light, the dashboard where the book sits and the book are both at rest. When the car begins to move forward, the dashboard moves forward with it. However as the book is not a part of the car, no force is directly acting on it, so the book so it stays at rest due to its inertia.
Therefore, as the car is moving forward, the stationary book appears to move backward from the reference point of the car, sliding off the dashboard.
A 2500-kg car is being pushed up a hill at an angle of 35 degrees. Determine the gravitational
force pulling down on the car if it is accelerating up the hill at a rate of 5 m/s/s.
Answer:
The force that pulls the car down is Wₓ = 14052.6 N and the one that pushes the car up is F = 26552.6 N
Explanation:
For this exercise we will use Newton's second law, let's set a reference system where the x axis is parallel to the plane, in the adjoint we can see the forces in the system.
sin 35 = Wₓ / W
cos 35 = W_y / W
Wₓ = W sin 35
W_y = W cos 35
Wₓ = 2500 9.8 sin 35
Wₓ = 14052.6 N
let's write the equations for each axis
and
Y axis
N-W_y = 0
N = W_y
X axis
F -Wₓ = m a
F = Wₓ + m a = mg sin 35 + m a
F = m (a + g sin 35)
let's calculate
F = 2500 (5 + 9.8 sin 35)
F = 26552.6 N
The force that pulls the car down is Wₓ = 14052.6 N and the one that pushes the car up is F = 26552.6 N
Based on its position in the periodic table of the elements, how many valence electrons does phosphorus (atomic number 15) have?
Answer:
5 Valence electrons
Explanation:
Answer:
5 Valence electrons
Explanation:
Hope this will help
A spring has a spring constant k = 20N/cm. What load is needed to produce an extension of 2.5cm?
ASAP please !
Answer:
50 N
Explanation:
We are given;
Spring constant; K = 20N/cm
Extension; Δx = 2.5 cm
We want to find the load which is the force. This is gotten from the equation;
F = k•Δx
F = 20 × 2.5
F = 50 N
Therefore the load needed is 50 N.
How much force must be applied to a 4 kg to get it to accelerate at 3
m/s^2?
Answer:
12 g i think
Explanation:
brainliest pls
A student drops a ball out of a helicopter flying 40.0m/s horizontally at an altitude (height) of 77.0m. Neglect drag.
How long did the ball remain in the air?
How far did the ball travel horizontally before striking the ground?
What is the netforce?
Answer:
6 Newtons to the left.
Explanation:
We can convert this into a generic algebra equation by giving directions positive and negative values.
The 6 will be positive, and the 10 and 2 will be negative.
Add 10 and 2 to have 12.
6-12 = -6.
Therefore you have 6 newtons to the left (negative).
how do you fix a broken foot
my sister is in literal tears and i dont have a phone and
our parents are out of the house rn
Dominique and her sister are practicing their basketball skills at the park. If both Dominique and her sister both throw their basketballs at the same time and they hit each other. What would happen to their basketballs? a) Only the basketball's speed would be changed b) Only the basketball's directions would be changed c) Both the basketball's speed and direction would change d) Neither the basketball's speed nor direction would change
Answer:
Option C, Both the basketball's speed and direction would change
Explanation:
When two objects travelling with certain speed interact with each their internal forces changes and hence their motion changes simultaneously.
In general cases it is said that momentum is conserved. Momentum is nothing but just the product of mass and velocity.
As the motion of the football changes, then momentum also changes. Since mass is a constant value, it is the velocity of the football that changes.
Hence, both speed and direction of both the football changes.
Option C is correct
The body weighing 3.5 kg moves in the horizontal plane under the action of force F. During 3 s of movement the body traverses the path 25 m. Find the value of the force F acting on the body. Friction to be neglected.
Answer:
given..
m= 3.5
t= 3
d=25
f=?
now....a...
25=1/2a×9
a=50/9
f=ma=35/10×50/9=19.4N
A 5 Kg bowling ball is thrown at a stationary 1.6 Kg bowling pin at 5 m/s. If the final velocity of the ball is 2.5 m/s. The final velicoty of the bowling pin is _____m/s.
Answer: hope this helps
Explanation:
If the final velocity of the ball is 2.5 m/s, the final velocity of the bowling pin is 7.8125 m/s.
What is principle of conservation of momentum?According to the principle of momentum conservation, momentum is only modified by the action of forces as they are outlined by Newton's equations of motion; momentum is never created nor destroyed inside a problem domain.
According to the principle of momentum conservation, total momentum of an system remains conserved.
Total initial momentum = total final momentum
5 kg × 5 m/s + 1.6 kg × 0 m/s = 5 kg × 2.5 m/s + 1.6 kg × v
1.6 kg × v = 5 kg × 5 m/s - 5 kg × 2.5 m/s
v = (5 kg /1.6 kg) (5 m/s - 2.5 m/s)
= 7.8125 m/s
Hence, If the final velocity of the ball is 2.5 m/s, the final velocity of the bowling pin is 7.8125 m/s.
Learn more about momentum here:
brainly.com/question/24030570
#SPJ5
The frequency of the wave is 0.4 Hz. Calculate the period.
Answer:
use the formula
Explanation:
F = 1/T
where F = frequency and T = period
so put 0.4 Hz into the frequency
0.4 =1/T
T = 2.5 seconds
hope this helps
Que se debe cumplir para que la tabla permanezca en equilibrio Es un balancin con dos niños el primero m1= 45kg el segundo m2=38kg Del centro a la izquierda existe una distancia de 160 CM Hallar la distancia del centro a la derecha
formula: m1 * d1 = m2 * d2
datos:
m1= 45 kg
d1= 160 cm
m2= 38 kg
d2= x
reemplazamos datos en formula:
45kg * 160cm = 38kg * d2
El 38 pasa al otro lado de la igualdad a dividir:
(45kg * 160cm) / 38 kg = d2
Resolvemos: (kg se cancela con kg, quedando solo los cm)
7200cm / 38 = d2
Resultado:
d2 = 189.5 cm
Respuesta: La condición que se debe cumplir es que la distancia del centro al niño de la derecha sea de 189.5cm
A bear scratches his claws on a big pine tree. Does the bear do work on the tree? why or why not?
(btw it has to do with physics) ITS NOT A GENERAL QUESTION.
Answer:
The bear is actually sharpening his claws. That's the only reason he scratches a tree with his claws
Explanation:
PLS ANSWER FAST WILL GIVE BRAINLY TIMED TEST
use the equation solving a= F divided by M
Also use metres per second squared [m/s2]
A loaded coal wagon with a total mass of 20, 000 kg is pushed by a force of 300,000 N. What was the wagon's acceleration?
A house of mass 500 kg is lifted 25 m by balloons.
Calculate the increase in gravitational potential energy, Ep.
(g = 10 N/kg)
Enter your answer as a number - NO units
Please Help!! This is for my Science Assignment but I dont even know how to do the last part (d; Find frictional force)
Answer:
I known this much much except c and d. Hope this helps, thank you !!
Robert hook used an early microscope to observed a cork sample. How did this help contribute to cell theory?
Answer:
Robert Hooke used an early microscope to observe a cork sample. How did this help contribute to cell theory? It helped to show that cells contain water. ... It helped to show that some cells are visible to the naked eye.
Explanation:
If your teacher checks if it was copied just put it in your on words
Which one of the following is NOT a phenotype?
O Red Hair
O Brown Eyes
O Red/Green Blood
O Five foot tall girl
O These are all phenotypes
According to Newton’s third law of motion, when a hammer strikes and exerts force on a nail, the nail...
A)creates a friction with the hammer
B) disappears into the wood
C) exerts an equal force back on the hammer
D) moves at a constant speed
Answer:
C) Exert an equal force back on the hammer
Explanation:
Every action has an equal and opposite reaction
also just trust me.
Make me brainlist
A boy on a bicycle drags a wagon full of newspapers at 0.800 m/s for 30.0 min using a
force of 40.0 N. How much work has the boy done?
Answer:
=57600joules
Explanation:
Given data
Velocity =0.8m/s
Time = 30*60=1800 seconds
Distance =Velocity x time
Distance =0.8*1800
Distance =1440m
Work done = force x distance
Work done =40*1440
Work done =57600joules
Hence the work Done is 57600joules
How far must a spring with a spring constant of 64N/m be stretched to
store 0.32J of potential energy?
Answer:
0.1m
Explanation:
k = 64N/m
Ep = 0.32J
x = ?
Ep = 1/2 * kx²
make x the subject of the formula
x² = 2Ep/k
x = √(2Ep/k)
x = √(0.64/64)
x = √0.01
x = 0.1m
Georgia drops a brick from the top of an 80.0 m building. What is the velocity of the brick when it hits the ground?
Answer:
the velocity of the brick when it hits the ground is 39.60 m/s
Explanation:
Given;
height through which the ball is dropped, h = 80.0 m
the initial velocity of the brick, u = 0
The final velocity of the brick when it hits the ground is calculated as;
v² = u² + 2gh
v² = 0 + 2 x 9.8 x 80
v² = 1568
v = √1568
v = 39.60 m/s
Therefore, the velocity of the brick when it hits the ground is 39.60 m/s
A boat has a porthole window, of area 0.00849 m^2, 6.25 m below the surface. The density of sea water is 1027 kg/m^3. The air inside the boat is at 1 atm. What is the net force on the window?
Answer:
[tex]325.65\ \text{N}[/tex] outward.
Explanation:
[tex]\rho[/tex] = Density of water = [tex]1027\ \text{kg/m}^3[/tex]
g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]
h = Height of the water = 6.25 m
A = Area of the window = [tex]0.00849\ \text{m}^2[/tex]
[tex]P_i[/tex] = Internal pressure of the boat = [tex]1\ \text{atm}=101325\ \text{Pa}[/tex]
Pressure by the water on the window
[tex]P=\rho gh\\\Rightarrow P=1027\times 9.81\times 6.25\\\Rightarrow P=62967.9375\ \text{Pa}[/tex]
Net pressure on the window
[tex]P_n=P-P_i=62967.9375-101325=-38357.0625\ \text{Pa}[/tex]
Force is given by
[tex]F=P_nA\\\Rightarrow F=-38357.0625\times 0.00849\\\Rightarrow F=-325.651460625\ \text{N}[/tex]
Net force on the window is [tex]325.65\ \text{N}[/tex] outward.
Answer: 534.6 N
Explanation:
This answer works for Acellus!
Describe the buoyant force acting on the Lucia before the torpedo attack.
Answer:
Explanation: positive
A(n) _______ is a line in which waves move that are moving together all in the same phase
Light wave
Wave front
Incident beam
Dark wave
Answer:
wave front
Explanation:
wave front is an imaginary line of a wave that joins all adjacent points that are in phase,
so that's the definition, and you apply it to the question
it obviously can't be the rest
hope you get it
please mark it brainliest
Answer:
B Wave front
Explanation:
EDG 21