Answer:
1) an expression for the car's speed is given as
v = u + at
where
v is the car's speed
u is the initial speed of the car
a is the car's acceleration
t is the time spent accelerating
2) The car does not hit the tree limb
Explanation:
The initial velocity of the car = 0 m/s (since it accelerates from rest)
acceleration of the car = 1.76 m/s
time spent accelerating = 20 s
For the car's speed just before the driver begins braking, we use the expression
v = u + at
where v is the final speed of the car just before the driver begins braking
u is the initial velocity with which the car starts moving
a is the acceleration of the car
t is the time spent accelerating from u to v
substituting values, we have
v = 0 + 1.76(20)
v = 0 + 35.2
the car's speed v = 35.2 m/s
In this time the car accelerates, the car moves a distance given by
s = ut + [tex]\frac{1}{2}[/tex]a[tex]t^2[/tex]
where s is the distance covered in this time
u is the initial speed of the vehicle
a is the acceleration
t is the time taken
substituting, we have
s = 0(20) + [tex]\frac{1}{2}[/tex](1.76)[tex]20^{2}[/tex]
s = 0 + 352
distance s = 352 m
When the driver brakes, we have
time spent braking = 5 s
acceleration = -5.93 m/s
and the distance to the limb = 550 m from where the car begun
to get the distance covered in this period, we use the expression
s = ut + [tex]\frac{1}{2}[/tex]a[tex]t^2[/tex]
where s is the distance traveled at this time
u is the speed of the car before it starts braking = 35.2 m/s
a is the acceleration at this point
t is the time taken to decelerate to a stop
substituting values, we have
s = 35.2(5) + [tex]\frac{1}{2}[/tex](-5.93 x [tex]5^2[/tex])
s = 176 - 74.125
s = 101.88 m
Total distance moved by the car = 352 m + 101.88 m = 453.88 m
Since the total distance traveled by the car is less than the distance from the starting point to the place where the tree limb is, the car does not hit the tree limb.
What is the approximate height of the average adult in centimeters?a. 100b. 200c. 300
Answer:
Option B
200 cm
Explanation:
From statistical evidence, the average height of an adult is about 200cm. This is like 2m or 6.56 feet.
Despite the fact that there are some exceptions; with some adults reaching heights of about seven feet, and some dwarfs who stand only about 1 m tall, most adults only grow to about 200cm in height before they start shrinking due to old age.
By how many orders of magnitude is the distance to the nearest stars greater than the orbital radius of Neptune
Which elements are found in all four components of Earth?
Answer:
oxygen silicon aluminun iron
Usted coloca un recipiente con de mar sobre una bascula y toma nota de la lectura que indica la báscula . Ahora usted suspende la estatua del ejemplo 14.5 en el agua ( figura 14.18 ). Cómo cambia la lectura de la bascula ? ) Se incrementa en 7.84 N; ii) disminuye en 7.84 N: ) permanece igual: ) ninguna de las respuestas anteriores es correcta . cambia la lectura de la báscula cuando la estatua se sumerge en el agua?
Answer:
t the apparent weight of the body decreases when it is submerged in water,
F'_{e} = mg - ρ_liquid g V
Explanation:
When a container is placed on a scale it falls due to the weight of the body and the needle attached to the spring shows the value of the weight that is proportional to the displacement of the spring.
When the body is immersed in a container with water, it exerts a push on the body, so its apparent weight decreases and the compression of the scale is less, therefore it indicates a smaller weight of the body.
Let's write the equilibrium equation for the body is placed on the scale without water
[tex]F_{e}[/tex] - W = 0
F_{e} = W
Let us propose the equilibrium equation for this case
F'_{e} + B - W = 0
where F'_{e} is the elastic force, B the push of the liquid and W the weight of the body
F'_{e} = W -B
The thrust of the liquid is given by the Archimedean principle which says that it is equal to the weight of the dislodged liquid
B = ρ g V
F'_{e} = mg - ρ_liquid g V (1)
we use the density concept
ρ_body = m / V
we substitute
F'_{e}= g V (ρ_body - ρ_agua) (2)
F'_{e} < F_{e}
We see from expression is 1 and 2 that the apparent weight of the body decreases when it is submerged in water,
To know the specific value of the decrease, the weight of the body in the air or its density and volume must be known
A ball is thrown upward with a speed of 28.2 m/s.A. What is its maximum height?B. How long is the ball in the air?C. When does the ball have a speed of 12m/s?
Answer:
(A) The maximum height of the ball is 40.57 m
(B) Time spent by the ball on air is 5.76 s
(C) at 33.23 m the speed will be 12 m/s
Explanation:
Given;
initial velocity of the ball, u = 28.2 m/s
(A) The maximum height
At maximum height, the final velocity, v = 0
v² = u² -2gh
u² = 2gh
[tex]h = \frac{u^2}{2g}\\\\h = \frac{(28.2)^2}{2*9.8}\\\\h = 40.57 \ m[/tex]
(B) Time spent by the ball on air
Time of flight = Time to reach maximum height + time to hit ground.
Time to reach maximum height = time to hit ground.
Time to reach maximum height is given by;
v = u - gt
u = gt
[tex]t = \frac{u}{g}[/tex]
Time of flight, T = 2t
[tex]T = \frac{2u}{g}\\\\ T = \frac{2*28.2}{9.8}\\\\ T = 5.76 \ s[/tex]
(C) the position of the ball at 12 m/s
As the ball moves upwards, the speed drops, then the height of the ball when the speed drops to 12m/s will be calculated by applying the equation below.
v² = u² - 2gh
12² = 28.2² - 2(9.8)h
12² - 28.2² = - 2(9.8)h
-651.24 = -19.6h
h = 651.24 / 19.6
h = 33.23 m
Thus, at 33.23 m the speed will be 12 m/s
Einsteins general theory of ————- describes the relationship
between energy and matter, and is major event in the history
of science.
Answer:
Special relativity.
Explanation:
Einstein's general theory of special relativity describes the relationship
between energy and matter, and is major event in the history
of science.
In 1905, Albert Einstein a noble physicist developed a theory that forms part of the basis of modern physics and one of the major event in the history of science, this theory was known as the theory of special relativity.
The theory of special relativity gives the relationship between space and time for any object that is moving at a uniform speed in a straight line, typically at the speed of light.
Simply stated, the theory of special relativity describes how a change in the speed of an object affect or relate with the measurement of space, time and mass. This ultimately implies that, as an object approach the value of light speed, it gains an infinite amount of mass and as such it is unable to travel faster than light.
The theory of special relativity by Albert Einstein gave birth to one of the most famous equation in science;
[tex]E = mc^2[/tex]
The equation illustrates, Energy equals mass multiplied by the square of the speed of light.
Where; E = Energy.
M = Mass.
C = Speed of light.
From the above equation, we can deduce that the mass of an object increases with speed and that mass is equivalent to energy, thus matter (mass) can be interchanged with energy.
A race car has a maximum speed of 0.104 km/s .What is this speed in miles per hour ?
Answer:
232.641374 mph
Explanation:
A race car has a maximum speed of 0.104km/s
Let X represent the speed in miles per hour
Therefore the speed in miles per hour can be calculated as follows
1 km/s = 2,236.936292 mph
0.104km/s = X
X = 0.104 × 2,236.936292
X = 232.641374
Hence the speed in miles per hour is 232.641374 mph
Speed of the car can be defined by the ratio of distance traveled by time elepsed. The speed of the given car is 233.212 miles/hr.
What is speed?
Speed can be defined by the change in position of an object in a given period of time.
[tex]\bold {Speed = \dfrac {Distance }{Time}}[/tex]
Given here,
The speed of the car is 0.104 km/s
Since 1 km = 0.621
So, 0.104 km = 0.0646
and 1 s = 0.000277
So, the speed of the car in miles per hour,
[tex]Speed = \dfrac {0.0646 \rm \ miles }{0.000277}\\\\ Speed =233.212 \rm \ miles/hr[/tex]
Therefore, the speed of the given car is 233.212 miles/hr.
Learn more about unit conversion:
https://brainly.com/question/4736731
As an object in motion becomes heavier, its kinetic energy _____. A. increases exponentially B. decreases exponentially C. increases proportionally D. decreases proportionally
Answer:
c
Explanation:
4. Velocity can be calculated using the following equation
v= Ad/t
Mass (kg)
Displacement (m)
Velocity (m/s)
7.58
3.56
35.65
Given the data above from an experiment, calculate the amount of time the object was
in motion
3.56 displacement ( m )
Suppose you are designing an amplifier and loudspeaker system to use at a rock concert. You want to make it as loud as possible. How can you design the system to maximize the volume? Explain your answer?
Hi, I’m very confused by this question. Is it referring to the right hand rule to predict where the force and current will face?
Thanks for helping!
Answer is given below
Explanation:
Audio power amplifiers are found in all types of sound systems, including sound reinforcement, public address and home audio systems, as well as musical instrument amplifiers such as guitar amplifiers. This is the last electronic step in the general audio playback series before sending the signal to the loudspeaker. So when we want maximum volume or loud sound, we have to get it with maximum output and high input and low output impedanceWhat is an atmospheric window?
A. A region in the atmosphere where light can get through
B. A region in the atmosphere where infrared radiation can penetrate
C. A range of wavelengths of electromagnetic radiation which transmit through the Earth's atmosphere
D. A part of the upper atmosphere with depleted ozone
E. Only A and D above
Answer:
A
Explanation:
Because it is a region in atmosphere that allows an particular wavelength of EMWs to pass through and of the options above only visible light is allowed to pass through
What is a chemical change?
Scientists repeat experimental findings in order to:__________.
A) improve upon experimental design.
B) eliminate unseen errors.
C) both A and B
D) neither A nor B
Answer:
neither A nor B
Explanation:
There are a lot of reasons, quite handful of them. About why scientists repeat experiments.
They do so sometimes to persistently verify the results they have gotten. Another reason is so as to be able to study and improve them in other ways.
This is just 2 of the very many reasons why scientists repeat experiments. Remember the popular saying, that practice makes perfect? yeah, that's just it
I hope you understand. Thanks
How many planets are there?
Answer:
There are eight planets in our Solar System.
Explanation:
Answer:
8
Explanation:
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
PLEASE HELP 3 + 2 ∙ 4 = 3 + (2 ∙ 4) True False
The given expression 3 + 2 ∙ 4 = 3 + (2 ∙ 4) is absoulutely correct so it is True.
What is the arithmetic operator?Arithmetic operators are four basic mathematical operations in which summation, subtraction, division, and multiplication involve.,
Summation = addition of two or more numbers or variable
For example = 2 + 8 + 9
Subtraction = Minus of any two or more numbers with each other called subtraction.
For example = 4 - 8
Division = divide any two numbers or variable called division.
For example 4/8
Multiplication = to multiply any two or more numbers or variables called multiplication.
For example 5 × 7.
Given,
3 + 2 ∙ 4 = 3 + (2 ∙ 4)
We know that in every calculation we cannot separate multiplication and need to solve them first
So,
3 + 8 = 3 + 8
11 = 11
Hence, 3 + 2 ∙ 4 = 3 + (2 ∙ 4) is absoulutely correct.
To learn more about the arithmetic operators,
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For a circuit find the total potential differences if two resistors
of resistance R1 and R2 respectively kept series wise for a
current I passing through it.
-- If the two resistors are connected in series, then they behave like a single resistor whose resistance is (R₁ + R₂) ohms.
-- For any resistance, the potential difference (volts) across the resistance is V = (current) x (resistance) .
-- So in THIS circuit, V = I x (R₁ + R₂) .
A linear accelerator uses alternating electric fields to accelerate electrons to close to the speed of light. A small number of the electrons collide with a target, but a large majority pass through the target and impact a beam dump at the end of the accelerator. In one experiment the beam dump measured charge accumulating at a rate of -2.0 nC/s. How many electrons traveled down the accelerator during the 2.0 h run
Answer:i
9E13 ELECTRONS
Explanation:
First we find the number of charges in two hrs
Which is - 2x 7200=- 14400NC
So no of electrons is now q/e
-144x10^-7/-1.6*10^-19
= 9*10^13
The work done when a force moves a body through a distance of 15m is 1800j. What is the value of the force applied
Answer:
120 Newtons.
Explanation:
Work(Joules) = Force(Newtons) × Distance(Meters)
If we need to find the Force, the equation changes.
To find Force, you have to divide the Work done from the Distance. Have a look at the picture above.
Four different vehicles are shown. Assume that all four vehicles are traveling at the same speed on a highway. Which is true about the kinetic energy of the vehicles?
A. The motorcycle has the most kinetic energy because it has the least mass.
B. All of the vehicles have the same kinetic energy because they are moving at the same speed.
C. The delivery van has the greatest kinetic energy because its mass is greater than that of the other
vehicles.
D. The delivery van has the greatest kinetic energy because it has the most tires in contact with the
pavement.
Answer:
Option C. The delivery van has the greatest kinetic energy because its mass is greater than that of the other
vehicles.
Explanation:
Kinetic energy is the energy of an object in motion. Mathematically, it is expressed as:
K.E = ½mv²
Where:
K.E is the kinetic energy.
m is the mass of the object.
v is the velocity of the object.
From the formula above, we can say that:
Kinetic energy is directly proportional to the mass of the object and the square of the velocity of the object. This simply means that objects with higher mass will have a greater kinetic energy than objects will lighter mass even if their velocities are the same.
From the question given above, it is obvious that the delivery van has a greater mass than the rest object.
Therefore, the delivery van will have the greatest kinetic energy because its mass is greater than that of the other
vehicles.
A certain electromagnetic wave traveling in seawater was observed to have an amplitude of 98.02 (V/m) at a depth of 10 m, and an amplitude of 81.87 (V/m) at a depth of 100 m. What is the attenuation constant of seawater
Answer:
The value is [tex]\alpha = 0.002 Np/m[/tex]
Explanation:
From the question we are told that
The first amplitude of the wave is [tex]E_{max}1 = 98.02 \ V/m[/tex]
The first depth is [tex]D_1 = 10 \ m[/tex]
The second amplitude is [tex]E_{max}2 = 81.87 \ (V/m)[/tex]
The second depth is [tex]D_2 = 100 \ m[/tex]
Generally from the spatial wave equation we have
[tex]v(x) = Ae^{-\alpha d}cos(\beta x + \phi_o)[/tex]
=> [tex]\frac{v(x)}{v(x)} =\frac{ Ae^{-\alpha d}cos(\beta x + \phi_o)}{ Ae^{-\alpha d}cos(\beta x + \phi_o)}[/tex]
So considering the ratio of the equation for the two depth
[tex]\frac{A}{A_S} = \frac{e^{-D_1 \alpha }}{e^{-D_2 \alpha }}[/tex]
=> [tex]\frac{98.02}{81.87} = \frac{e^{-10 \alpha }}{e^{-100 \alpha }}[/tex]
=> [tex]\alpha = \frac{0.18}{90}[/tex]
=> [tex]\alpha = 0.002 Np/m[/tex]
separating paper from a mixture by burning it is it a physical change true or false
Answer:
false
Explanation:
burning something is a chemical change
A major advantage of case studies is ________.
Assess platos theory of the forms from Aristotle's standpoint. is he correct? Explain..it’s philosophy
Answer:
The task of philosophy, for Plato, is to discover through reason (“dialectic”) the nature of the Forms, the only true reality, and their interrelations, culminating in an understanding of the most fundamental Form, the Good or the One. Aristotle rejected Plato’s theory of Forms but not the notion of form itself. For Aristotle, forms do not exist independently of things—every form is the form of some thing. A …
Explanation:
The Sun emits a ray of light with a wavelength of 550 nm.a. What is its frequency?b. The ray falls on a flat piece of quartz at an angle of 70º relative to the surface. The ray refracts to an angle of 76.46º relative to the surface. What is the index of refraction for quartz?c. What is the speed of light in quartz?
Answer:
Frequency of light = 5454.5 GHz
Refractive index = 1.46
speed of light in quartz = 2.05 x 10^8 m/s
Explanation:
The wavelength of the light λ = 550 nm = 550 x 10^-9 m
frequency = ?
Frequency of light f = c/λ
where
c is the speed of light = 3 x 10^8 m/s
substituting, we have
f = (3 x 10^8)/(550 x 10^-9)
frequency f = 5.4545 x 10^14 Hz
==> 5454.5 GHz
The relationship between refractive index is given as
n1 sinθ1 = n2 sinθ2
where
n1 is the refractive index of air = 1
θ1 is the angle of incidence = (90 -70) = 20°
θ2 is the angle of refraction = (90 - 76.46) = 13.54°
n2 is the refractive index of quartz
substituting values, we have
1 x sin 20 = n2 x sin 13.54
0.3420 = n2 x 0.2341
refractive index of quartz n2 = 0.3420/0.2341 = 1.46
From n = c/v
where
n is the refractive index of quartz
c is the speed of light in air = 3 x 10^8 m/s
v is the speed of light in quartz = ?
substituting values, we have
1.46 = (3 x 10^8)/v
v = (3 x 10^8)/1.46 = 2.05 x 10^8 m/s
2. If you are driving at a constant velocity of 5 m/s what is your
acceleration?
Which law of motion is this an example of? Newton's 1st 2nd or 3rd law?
Answer:
May be it is first law of motion.An initially neutral glass rod is rubbed with silk. It becomes positively charged by_____.a) electrons are created on the rod.
b) electrons are transferred from the silk to the rod.
c) protons are transferred from the silk to the rod.
d) protons are transferred from the rod to the silk.
e) electrons are transferred from the rod to the silk.
Answer:
e) electrons are transferred from the rod to the silk.
Explanation:
An initially neutral glass rod contains equal number of electron and proton.
If the rod becomes positively charged after being rubbed with silk, then the rod must have lost some its electron to the silk since electrons are more mobile than protons, leaving the rod with excess positive charge (protons), and the silk will be negatively charged (excess electron).
Thus, the rod becomes positively charged by transfer of electrons from rod to the silk.
e) electrons are transferred from the rod to the silk.
a battery of 6v is connected in series with resistors of 0.1 ohm, 0.15 ohm, 0.2 ohm, 0.25 ohm and 6 ohm. how much current would flow through 0.2 ohm resistors
Answer:
0.9 Amps
Explanation:
Ohm's law: Voltage = Current x Resistance
Rearrange equation:
Current =Voltage/Resistance
Voltage=6v
In a series circuit the total resistance is the sum of all the resistors so the total resistance = 0.1+0.15+0.2+0.25+6=6.7 Ohms
6/6.7 = 0.9 (1dp) Amps
Because it is a series circuit, the current is the same throughout the entire circuit, all the resistors have a current of 0.9 Amps.
Hope this helped!
Samantha is 1.44 m tall on her eleventh birthday and 1.68 m tall on her twelfth birthday. By what factor has her height increased? By what percentage?
Answer:
Given initial height h¹= 1.44
Final height h²=1.68
So factor increase is 1.68/1.44²= 1.17
Percentage increase will be
1.68-1.44/1.44*100%=16.7%
Calculate the speed for a car that went a distance of 125 miles in 2 hours time.
Answer:
65 miles per hour
Explanation:
Speed= Distance/Time
Following this formula, we just need to insert the values.
The distance is 125 miles and the time is 2 hours
125=2=65
65 miles per hour
The speed of the car was exactly 125 mi per 2 hours.
In a more familiar unit, 125mi/2hr = 62.5 mi/hr.