what activities belong at the top of the physical activity pyramid
Answer: Cut down on watching tv, sitting down for more than 30 minutes at a time, and playing video games.
Explanation:
You get in your car to drive to school at 7:33 am and drive 10 miles north at a constant speed until 7:45
am, when you realize you left your homework on the kitchen table. You turn around and drive 10 miles
south back to your house and retrieve your homework at 8:00 am. You get back in the car and drive 15
miles north to school at a constant speed arriving at school at 8:29 am sharp, just in time to make it
before the bell rings.
e
Answer:
5.) 16.8 m/s
6.) 16.1 mph
7.) Moving fast.
Explanation:
5.) From the question, the total time will be:
7:33 am to 7:45 am = 12 minutes
As the car turns around,
7 : 45 am to 8 : 00am = 15 minutes
As you get back in the car and drive 15
miles north to school at a constant speed arriving at school at 8:29 am
8:00am to 8:29 am = 29 minutes
Total time = 12 + 15 + 29 = 56 minutes
Convert the minutes to second by multiplying the result by 60
Total time = 56 × 60 = 3360 seconds
Total distance covered will be
10 miles + 10 miles + 15 miles = 35 miles
Convert mile to meter by multiplying the result by 1609.344
35 × 1609.344 = 56327.04
Speed is a scale quantity. It only involves magnitude but no direction.
Average speed = total distance/total time
Average speed = 56327.04/3360
Average speed = 16.764 m/s
6.) Velocity = displacement/time
Velocity is a vector quantity. We will consider both the magnitude and direction
Total displacement = 10 miles - 10 miles + 15 miles = 15 miles.
Total time = 56 minutes
Convert minutes to hours by dividing it by 60
Total time = 56/60 = 0.93 hours
Substitute the time and displacement into the formula
Velocity = 15/0.93 = 16.07 mph
7.) . If you looked at your speedometer on your drive to school and it read 30mph, this value describes you move with a fast speed.
Which statements best describe X-rays?
Answer:x rays are electromagnetic waves.
x rays are transverse waves
x rays travel at the speed of light
Explanation:
state two factors that affect the turning effect of force
Answer:The first is the magnitude of the force applied on the body and the second is the perpendicular distance from the line of action of force and the axis of rotation of the body.
Explanation:
tree
5. A carge pinnore camera has a magnification of 0.050 for a
located 5.on from the camera. Klhat is the size of the image
screen?
son
the
Solution
Answer:
Explanation:
Size of the image: 2 cmIn order to calculate the size of the image, we can use the following proportion:wherep = 80 m is the distance of the tree from the pinholeq = 20 cm = 0.2 m is the distance of the image from the pinhole = 8 m is the heigth of the object is the height of the imageBy re-arranging the proportion, we find2) Magnification: 0.0025The magnification of a camera is given by the ratio between the size of the image and the size of the real object:so, in this problem we have
write the different between the fall of a parachute on earth and its fall on the moon?on what condition does a body have free fall?
Answer:
Shown from explanation
Explanation:
You have heard that expression what ever goes up must come down that's usually used to mean when you throw an object up, it comes down on its accord. This is due to a force on the earth that occurs in nature known as gravity.
So when an object falls under this influence it's said to fall freely.
Note not all heavenly bodies have gravitational pull, from experience by scientists who went to the moon they found out whatever goes up keeps flying endlessly so in that case an external force is needed to keep objects in the moon on ground level.
Hence the parachute falls on earth freely without an external force but on the moon it must fall with an external force inputed on the parachute system.
This means in the earth we have free fall but in the moon no such thing exist. So a body falls freely when there is gravity.
An injured monkey sits perched on a tree branch 9 m above the ground, while a wildlife veterinarian is kneeling down in the bushes 90.0 m away attempting to subdue the monkey with a tranquilizer gun. The vet knows that the moment the gun fires, the monkey will be frightened and fall down from the branch. At what angle up from the ground must the veterinarian aim the gun so that the tranquilizer dart will hit the falling monkey? Given the angle, what is minimum speed at which the tranquilizer dart must leave the gun to still hit the monkey?
Answer:
The hunter should aim directly at the perched monkey because the tranquilizer dart will fall away from the line sight at the same rate that the monkey falls from its perch.
Tan theta = 9 / 90 = .1 so theta = 5.71 deg
The time for the monkey to reach the ground is
t = (2 h / g)^1/2 = (18 / 9.8)^1/2 = 1.36 sec
So the horizontal speed of the dart must be at least
Vx = 90 m / 1.36 sec = 66.4 m/s
Vx = V cos theta
V = 66.4 m/s / cos 5.71 = 66.7 m/s
The angle of projection of the tranquilizer dart is 5.7⁰
The horizontal speed of the tranquilizer dart is 66.5 m/s
The given parameters;
vertical position of the monkey, y = 9 mhorizontal position of the veterinarian, x = 90The angle of projection of the tranquilizer dart is calculated as;
[tex]tan(\theta) = \frac{y}{x} \\\\tan(\theta) = \frac{9}{90} \\\\tan(\theta) = 0.1\\\\\theta = tan^{-1}(0.1)\\\\\theta = 5.71 ^0[/tex]
The speed of the tranquilizer dart is calculated as;
X = v₀ₓt
where;
t is the time to reach maximum height
X is the horizontal displacement = 90 m
The time to reach maximum height is calculated as;
[tex]h = v_0_yt + \frac{1}{2} gt^2\\\\h = 0 + \frac{1}{2} gt^2\\\\h = \frac{1}{2} gt^2\\\\t = \sqrt{\frac{2h}{g} } \\\\t = \sqrt{\frac{2\times 9}{9.8} } \\\\t = 1.36 \ s[/tex]
The horizontal speed of the tranquilizer dart is calculated as;
[tex]X = v_0cos(\theta) \times t\\\\90 = v_0\times cos(5.71) \times 1.36\\\\90 = 1.353 v_0\\\\v_0= \frac{90}{1.353} \\\\v_0 = 66.5 \ m/s[/tex]
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The gravitational force between two students sitting beside each other on Earth is
Answer:
Fgrav. = GM1×M2/R2
Explanation:
Gravitational force is mostly related
to planetary bodies by Newton's law of gravitation which states that the gravitional force is proportional to the product of the mass of the object and inversely proportional to the square of the distance between them.
Hence in this case the Gravitational force,
Fgrav. = GM1×M2/R2
M1 and M2 are the mass of the two students and R is their distance apart
G is a constant known as gravitational constant.6.67408 × 10-11 m3/kgs2
explain why atmospheric pressure decreases towards higher altitudes
Answer:
At higher elevations, there are fewer air molecules above a given surface than a similar surface at lower levels. ... Since most of the atmosphere's molecules are held close to the earth's surface by the force of gravity, air pressure decreases rapidly at first, then more slowly at higher levels.
Explanation:
happy to help:)
A 31.7 kg kid, initially at rest, slides
down a frictionless water slide at 53.2º.
How fast is she moving 3.45 s later?
Answer:
34.55m/s
Explanation:
Now from Newton's law of motion;
V= U+ a×t
V- final velocity
U- initial velocity = 0m/s
a- acceleration
t- time
Note that a = g/cos53.2°
Now g is acceleration of free fall due to gravity
This is a vertical acceleration since the course of motion is along a plane inclined at 53.2° to the height of the pool.
Also from trigonometry identity
cos 53.2°= vertical component a/ acceleration ( cos a = adjacent/hypothenus)
If we assume g = 9.8m/S2 { a generally given value}
Substituting t = 3.45s as the time of consideration, we have;
V = 0 + (9.8/cos53.2°)×3.45
= -34.55m/s
Note the -ve sign is just telling us this velocity is causing the object to move down.
Hence V = 34.55m/s
Answer:
27.07 m/s
Explanation:
this is the right answer
Which quantity Has the same unit as potential difference
Answer:
Voltage.
Explanation:
A ramp is a simple machine called the
a. wedge
b. pulley
c. inclined plane
d. lever
Answer:
Inclined Plane is the answer
Answer:
Inclined plane
Explanation:
It is called Inclined plane since it is a flat surface at an angle.
4 answers. Anyone know?
Answer:
lift
weight
thrust
air resistance
Explanation:
plz mark me as brainliest
Answer: Upthrust, lift, air resistance, and thrust
Explanation:
All of these 4 elements are taken into account during the design and creation of a plane.
what is web browser
Answer:
A web browser is a software application for accessing information on the World Wide Web
Answer:
web browser (commonly referred to as a browser) is a software application for accessing information on the World Wide Web. When a user requests a web page from a particular website, the web browser retrieves the necessary content from a web server and then displays the page on the screen.
Explanation:
PLEASE HELP!!!!!
When describing image formation for plane mirrors, what is an important rule
to remember about light rays?
Answer: The image formed by a plane mirror is always virtual (meaning that the light rays do not come from the image), upright and of the same shape and size as the object it is reflecting.
Answer: B. The angle when it leaves is the same as the angle when it hits
Explanation:
Apex
I NEED ANSWER RN OR ILL BE DED
Answer:
i) O m/s² as velocity is constant
ii) 20m/s
iii)Hint:Calculate the area of the graph,that is;below the line, for the first 15 seconds only
Hope this helps.
What happens when a sound wave passes from water into air
Answer:
Explanation:
Sounds travel faster in object having high density proportion or matter. This is because particles vibrates and causing the other particle near to as well vibrate. Hence, when sound is moving from a higher dense medium like Water, the rate of traveling is high compare to it moving in air with less dense.
would iron and carbon from metallic bonds
Answer:
NO
Explanation:
Since iron is a metal and carbon is a non- metal, they cannot form a metallic bond.
would iron and carbon form metallic bonds
Answer:
NO.
Explanation:
METALLIC BOND IS ONLY IN METALS.
Since iron is a metal and carbon a non- metal, they cannot form a metallic bond.
Please explain it’s in the photo
Answer:
Since air resistance actually stops vehicles and goes in a vector opposite to the direction of the vehicle and slows it down. Vehicles would want to make vehicles aerodynamic. Many cars bump into air molecules therefore making air resistance. Aerodynamic cars will lesser the allowance of bumping into said molecules. Thats why cars like to cut down on air resistance
Air resistance is friction.
-- Friction steals kinetic energy.
-- A car gets kinetic energy by burning gasoline, and uses the kinetic energy to get where it needs to go.
-- If anything steals the car's kinetic energy, then the car has to burn more gasoline to get where it needs to go.
-- Gasoline costs money.
-- Anything that steals a car's kinetic energy costs you more money to operate the car.
(Another thing that takes kinetic energy away from the car is the car's brakes. The driver uses the brakes when he WANTS to slow down or stop, so it's not stealing, but it still costs kinetic energy and money.)
Which of these would not improve accuracy?
A)Taking a bigger sample size
B)Using a bigger range of the independent variable
C)Using measuring instruments that can read to a greater number of decimal places
D)Remove anomalies
If two similar large plates each of area having surface charge density is +a and -b are separated by a distance d in air find the expression for the potential difference and capacitance between them
Answer:
a. V = (a - b)d/2ε₀ b. 2ε₀A/d
Explanation:
a. The potential difference between the plates
Using Gauss' law, we first find the electric field between the plates
ε₀∫E.dA = Q where Q = charge enclosed, E = electric field
Now Q = [a +(-b)]A = (a - b)A where + a and -b are the surface charge densities of the plates and A is the area of the plates.
ε₀∫E.dA = Q
ε₀∫EdAcos0 + ε₀∫EdAcos0 = (a - b)A
ε₀E∫dA + ε₀E∫dA = (a -b)A
ε₀EA + ε₀EA = (a -b)A
2ε₀EA = (a -b)A
E = (a - b)/2ε₀
We now find the potential difference, V between the plates from
V = ∫E.dl
V =E∫dl
V = Ed where ∫dl = d the distance between the plates.
V = (a - b)d/2ε₀
b. The capacitance between them
Capacitance C = Q/V
= (a - b)A ÷ (a - b)d/2ε₀
= 2ε₀A/d
Which of these objects has the largest volume?
Answer:
The balloon
Explanation:
Since there are 100 cm or 1000 mm in a meter, you can rewrite the dimensions in the following way:
A cube of metal with a volume of 10,000 mm^3
A spherical balloon with a volume of 50,000,000 mm^3
A sample of water with a volume of 1,000 mm^3
Therefore, the balloon clearly has the most volume. Hope this helps!
Answer:
spherical baloon
Explanation:
change all the measurements to be one I.e convert the m³ and mm³ to cm³
2)1m³=1000000cm³ what about 0.05m³
balloon =50000cm³
3)1cm3=1000mm³
water=1cm³
1)cube=10cm³ so which is the greatest
=spherical baloon
A car has a kinetic energy of 1.9 × 103 joules. If the velocity of the car is decreased by half, what is its kinetic energy?
Answer:
475 J
Explanation:
Kinetic energy is calculated by one half of the product of mass and velocity squared or expressed as:
KE = 1/2 (mv²)
We calculate as follows:
KE1 = 1/2 (mv²) = 1.9 * 10^3 joules
KE2 = 1/2 (m(v/2)²) = 1/2 (mv²/4)
KE2 = 1.9 * 10^3 joules / 4 = 475 J
the fireball___ ___when moving___
Answer:
the fireball flamed dangerously when moving quickly
Explanation:
im prbly wrong idk
1. How many digits does the frog have on each of its forelegs and how many on each of its
hind legs?
Answer:
A frog has four digits on its fore legs
A frog has five digits on its hind legs
Explanation:
Biologically, digits refer to the fingers and toes of animals (mostly vertebrates).
A frog is known to have only four digits on its fore limbs (which are not webbed). They usually use this for steering themselves in the water.
A frog also has five digits on each of its hind legs. These are webbed, and are used for swimming in water.
An object is placed at 1.5 m from a convex lens with a focal length of 1.0 m.
a. Use the thin lens equation to determine the image distance from the lens.
b. If the object height is 2.0 m, what is the image height?
c. Is the image real or virtual? Is the image inverted or upright?
What is the wavelength of a 1.28 x 10^17 Hz wave?
Answer:
The wavelength of the wave is 2.34 nm.
Explanation:
It is required to find the wavelength of a [tex]1.28\times 10^{17}\ Hz[/tex] wave. A wave moves with a speed of light. Speed of a wave is given in terms of wavelength and frequency. So,
[tex]v=f\lambda[/tex]
[tex]\lambda=\dfrac{c}{f}\\\\\lambda=\dfrac{3\times 10^8}{1.28\times 10^{17}}\\\\\lambda=2.34\times 10^{-9}\ m\\\\\text{or}\\\\\lambda=2.34\ nm[/tex]
So, the wavelength of the wave is 2.34 nm.
The wavelength of the wave is 2.34 × 10⁻⁹ meters.
Given the data in the question;
Frequency; [tex]f = 1.28*10^{17}Hz[/tex]Wavelength; [tex]\lambda =\ ?[/tex]
To determine the wavelength of the wave, we use the expression for the relations between wavelength, frequency and speed of light.
[tex]\lambda = \frac{c}{f}[/tex]
Where [tex]\lambda[/tex] is wavelength, f is frequency and c is speed of light ( [tex]3*10^8m/s[/tex] )
We substitute our values into the equation
[tex]\lambda = \frac{3*10^8m/s}{1.28*10^{17}Hz} \\\\\lambda = \frac{3*10^8m/s}{1.28*10^{17}s^{-1}} \\\\\lambda = 2.34 * 10^{-9}m[/tex]
Therefore, the wavelength of the wave is 2.34 × 10⁻⁹ meters.
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Why will a delivery truck filled with birds sitting on its floor be heavier than a truck with the same birds flying around inside.
The reason why a delivery truck filled with birds sitting on the floor be heavier than a truck with the same birds flying around is because when the birds are sitting on the floor, they are adding their weight to the truck.
Meanwhile, if the birds are flying around they aren't resting on the truck or touching it, so therefore their weight wouldn't be added to the truck.
The mass of the truck will remain the same as you cannot change the mass but the weight will vary depending on the items and objects placed in it.
If a transformer doubles its input voltage, what is the current in the secondary coil if the primary coil is 10 A.
Answer:
20Amp
Explanation:
Using the transformer formula
Vs/Vp = Ns/Np = Ip/Is
Vs/Vp = Ip/Is
Vp is the primary voltage = input voltage
Vs is the secondary voltage = output voltage
Ip is the current in the primary coil
Is is the amount of current in the secondary coil.
If the transformer doubles its input voltage Vp, its output voltage Vs will be
decreased by 2 but the output current will be doubled
Given the input current Ip = 10A, the current in the secondary coil (output current) will be doubled i.e Is = 2(10) = 20A
The current in the secondary coil be "50 A". To understand the calculation, check below.
Current and VoltageAccording to the question,
Current in primary coil, [tex]I_{in}[/tex] = 10 A
We know the relation,
Power = [tex]V_{in} I_{in}[/tex] = [tex]V_{out} I_{out}[/tex]
then,
→ [tex]V_{in} I_{in}[/tex] = [tex]V_{out} I_{out}[/tex]
By substituting the values,
[tex]V_{in}[/tex] × 10 = 2 [tex]V_{in} I_{out}[/tex]
By applying cross-multiplication,
10 = 2 [tex]I_{out}[/tex]
[tex]I_{out}[/tex] = [tex]\frac{10}{2}[/tex]
= 5 A
Thus the response above is correct.
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