Answer:
29.41%
Explanation:
Given that,
In 1630 at the beginning of European settlement, about 425,000,000 hectares of the United States were covered with trees.
By 2017, the area covered by trees was reduced to 300,000,000 hectares.
We need to find the percentage decrease in the area covered by trees between 1630 and 2017.
The percentage decrease in any value is given by :
[tex]\%=\dfrac{300,000,000 -425,000,000 }{425,000,000 }\times 100\\\\=29.41\%[/tex]
So, the percentage decrease in the area covered by the trees is 29.41%.
A car moving round a circular racing track takes 120s to do a lap of 8km what is the speed in km/hr.
Answer:
Solution in photo
Explanation:
A car moves around in a circular racing track, and it takes 120 seconds to do a lap of 8 km, so the speed in km/hr is 239.76 km/hr.
What is Speed?The speed of an object, commonly known as v in mechanics, is a scalar quantity that corresponds towards the size of the change in that object's position over duration or the size of the change in that object's position per unit of time.
The instantaneous velocity is the absolute maximum of the average speed as the time interval's duration gets closer to zero. The cruising pace of an object in a time interval is calculated by dividing its distance traveled by the time interval's duration. Velocity and speed are different concepts.
The given data according to the question is,
Time, t = 120 s
Distance, d = 8 km
s = 8/120
s =0.0666 km/sec or
s = 0.0666/1s × 3600
s = 239.76 km/hr.
Therefore, the speed is 239.76 km/hr.
To know more about Speed:
https://brainly.com/question/312131
#SPJ2
Which statement accurately compares the trends in atomic number and atomic mass in the periodic table?
O The atomic number increases from left to right, while the atomic mass increases from right to left.
O The atomic mass increases from left to right, while the atomic number increases from right to left.
O Both the atomic mass and the atomic number increase from left to right.
O Both the atomic mass and the atomic number increase from right to left.
Answer:
C.
That is your answer
You serve a volleyball with a mass of 1.4 kg. The ball leaves with a speed of 13 m/s. Calculate KE
Answer:
118.3 J
Explanation:
Givens:
m = 1.4 kg
V = 13 m/s
Formula for kinetic energy:
KE = (1/2)*(m)*(v)^2
KE = .5*(1.4 kg)*(13 m/s)^2
KE 118.3 J
J = Joules
identfy the parts of he atom that are labeied in the
dagram
Label A:
Label B
NEED THE ANSWE ASAP!
Answer :
Label A - nucleus.
Label B- electron cloud.
Explanation :
An atom is the smallest unit of a matter that consist of three subatomic particles which are electrons, protons and neutrons.
The protons and the neutrons are located inside the nucleus or the center of the nucleus where the mass of the an atom is concentrated.
The electrons are located around the nucleus.
The protons are positively charged, the electrons are negatively charged and the neutrons are neutral that means it has no charge.
In the picture, label A shows the nucleus.
Electrons has the ability to revolve around the nucleus in a fixed circular orbit. Electron cloud represents the spreading of the electrons energy.
In the picture, label B shows the electron cloud.
Hence, the label A - nucleus and label B- electron cloud.
Given the impulse acting on an object and the impact time which equation can be used to calculate the force applied to an object
Answer is D
Ndmdjdndbdjdkskd
The impulse acting on an object and the impact time, the equation F= I / Δt can be used to calculate the force applied to an object, therefore the correct answer is D.
What is impulse?The product of the average applied force and the time for which it is exerted is known as an impulse.
the mathematical relation for impulse is
Impulse = F * Δt
where F represents the force applied and Δt represents the time for which the force is applied
Thus, the correct equation that can be used to calculate the force applied to an object is F = I /Δt and the correct option is D.
Learn more about impulse, here
https://brainly.com/question/16980676
#SPJ2
Which graph accurately shows the relationship between kinetic energy and speed as speed increases?
Answer:
B
Explanation:
kinetic energy (KE) is the energy possessed by moving bodies. It can be expressed as:
KE = [tex]\frac{1}{2}[/tex]m[tex]v^{2}[/tex]
Where: m is the mass of the object, and v its speed.
For example, a stone of mass 2kg was thrown and moves with a speed of 3 m/s. Determine the kinetic energy of the stone.
Thus,
KE = [tex]\frac{1}{2}[/tex] x 2 x [tex]3^{2}[/tex]
= 9
KE = 9.0 Joules
Assume that the speed of the stone was 4 m/s, then its KE would be:
KE = [tex]\frac{1}{2}[/tex] x 2 x [tex]4^{2}[/tex]
= 16
KE = 16.0 Joules
Therefore, it can be observed that as speed increases, the kinetic energy increases. Thus option B is appropriate.
this is an area where two tectonic plates move towards each other with one going under the other plate?
Answer:Convergent boundaries are areas where plates move toward each other and collide. These are also known as compressional or destructive boundaries. Subduction zones occur where an oceanic plate meets a continental plate and is pushed underneath it. Subduction zones are marked by oceanic trenches.
pLS THANK ME AND VOTE ME BRAINLIEST ME
Explanation:
Which of the following statements about infrared telescopes is NOT true?
a. They are typically operated at lower temperatures.
b. They are especially helpful for viewing cool or obscured astronomical objects.
c. They were first built in the 1960s.
d. They are often placed on mountaintops.
e. They do not work well at high altitudes.
Answer:
a. They are typically operated at lower temperatures.
a. They are typically operated at lower temperatures.b. They are especially helpful for viewing cool or obscured astronomical objects.
Which of the following has zeros that are not significant?
2.05 m/s
10.0 J
1.30 N
100 kg
Answer: Either 10.0 J or 1.30 N
Explanation:
10.0 J
if it was 10.01 it would be significant, but its 10.0 which makes it a whole number
1.30 N
All zero's preceding the first integers are never significant. For example: 0.0078 has two significant figures. All zero's after the decimal point are always significant. For example: 4.500, 45.00 and 450.0 all have four significant figures
Answer:
100 kg
Explanation:
With the absence of a decimal point, only the 1 would be significant.
answer if you want to
Answer:
C
Explanation:
think of a diffuser
if an object with a mass of 248kg is lifted 76 meters in 18 seconds, how much power is used?
Explanation:
power = 1/2 mass × velocity^2 >>1
velocity = distance / time = 76 /18 = 4.2m
then power = 1/2 × 276 × (4.2)^2 = 138 × 17.64 = 2,434.3 jules.
help plz will give brainliest and dont answer if u dont know
Answer:
is highly motivated
Explanation:
How are the energy conversions of machines similar to the energy conversions in your body
Answer:
Explained below
Explanation:
When we eat food, our body gets chemical energy from it. Now, this chemical energy from the food is changed into some different energy forms that is useful to it. They include:
-Chemical to mechanical energy to aid in movement of muscles
- chemical to thermal energy to aid in regulating the body temperature.
- chemical to electrical energy to aid the brain in thinking.
Thus is similar to how a machine converts energy because machines also generate energy after being powered and convert to other forms of energy. For example, an alarm clock converts electrical energy to sound energy, hair dryer converts electrical energy to thermal/heat energy.
Transfer of charge by touching is called... induction or conduction?
Answer:
Transfer of charge by touching is called conduction.
what reactions do catalytic converters catalyze
Which lighting source has lower energy costs and a longer life but can be dangerous?
a. fluorescent
b. laser
c. incandescent
d. neon
Answer: I'm like 98% sure it's fluorescent cause it's got mercury
Explanation:
What is a type of light that the sun emits but a light bulb does not?
Gamma ray
X-ray
Ultra violet (UV)
Visible
Infrared (IR)
Microwave
Radio
Household lightbulbs don't emit radio, microwave, X-rays or gamma rays, and only a smidgen of ultraviolet.
The sun emits everything on the list.
The Sun emits many types of light , the ultraviolet, X-ray, and even gamma-ray, radio and infrared parts of the spectrum.
The light bulb emits very small amounts of UV light.
The Sun emits many types of light , the ultraviolet, X-ray, and even gamma-ray parts of the spectrum.But most of the Sun's light is in the infrared, visible, and ultraviolet parts of the electromagnetic spectrum.The Incandescent light bulbs, the most commonly used light bulbs in homes, give off small amounts of UV light. The UV light emitted by these bulbs is so small that it's impossible for human health to be affected in any way.Learn more:
https://brainly.com/question/2499551
When you heat water, it changes from-- *
A a gas to a liquid
B a liquid to a gas.
C a liquid to a solid
Answer:
Hi! It's B - liquid to a gas.
Why is a protective apron or lab coat important to use when working with acids?
Acids conduct electricity and contact could cause a shock.
Acids react with lipids and can cause damage to skin tissue.
Acids break down fabrics and can cause burns if the acids are strong.
Acids have a slippery feel and could result in a fall.
Answer:
Acids break down fabrics and can cause burns if the acids are strong.
Explanation:
A protective apron or lab coat is important when working with acids because acids break down fabrics and can cause burns if the acids are strong.
An acid is a substance that interacts with water to produce excess hydroxonium ions in an aqueous solution. A strong acid ionizes completely in solution. When they come in contact with a fabric, they break them down violently. So, if they come in contact with the skin, it causes a violent break down of body tissues. The apron acts a protective layer.Answer:
C
Explanation:
I got it right
why does the fire snake weight less than it was when it was on fire
Answer:
When Zoe weighs the ingredients (sugar and baking soda), it weighs 25 grams in total. When she weighs the “snake” it weighs 23 grams. This is because some carbon dioxide gas produced during the chemical reaction escapes into the air.
A dog starts at position x=2.50m, and undergoes a displacement of 8.25m. What is its final position?
Answer:
Civil law deals with behavior that constitutes an injury to an individual or other private party, such as a corporation. Examples are defamation (including libel and slander), breach of contract, negligence resulting in injury or death, and property damage.
Explanation:
Two charged objects originally felt 12N of attraction. One charge is changed from to 3C to 6C and their distance changes from 15cm apart to 45cm apart. What is the new force of attraction ?
Given that,
Initial force, F = 12 N
First initial charge, q₁ = 3C
First new charge, q₁' = 6C
Initial distance, r = 15 cm
New distance, r' = 45 cm
To find,
The new force of attraction.
Solution,
The force between two charges is given by :
[tex]F=k\dfrac{q_1q_2}{r^2}[/tex]
[tex]12=k\dfrac{3\times q_2}{15^2}\ ....(1)[/tex]
Let F' is the new force.
[tex]F'=k\dfrac{q_1'q_2'}{r'^2}[/tex]
[tex]F'=\dfrac{k\times 6\times q_2}{(45)^2}\ ...(2)[/tex]
As q₂ is same in this case.
Dividing equation (1) and (2) :
[tex]\dfrac{F}{F'}=\dfrac{k\dfrac{3q_2}{15^2}}{\dfrac{k\times 6\times q_2}{45^2}}\\\\\dfrac{12}{F'}=4.5\\\\F'=\dfrac{12}{4.5}\\\\F'=2.67\ N[/tex]
So, the new force of attraction is 2.67 N.
A 2.0 kg block is pulled across a horizontal surface by a 15 N force at a constant velocity.a. What is the net force acting on the block?
Answer:
0
Explanation:
the block is being pulled at a constant velocity meaning it has no acceleration. the rule is fnet=mass x acceleration so if theres no acceleration there is no force net!
A block of mass 2 kg is pulled across a surface with a force of 15 N then the net force acting on the block is 0.
What is Force?A force is an effect that can alter an object's motion according to physics. A force might cause an object has mass to accelerate when it changes its velocity, for, us when it moves away from rest. An obvious way to describe force is in terms of push or pull. A force is a vector quantity since it has equal magnitude and direction. It is calculated using the newton SI unit (N). Force is denoted by the letter F.
The net force exerted by an object was equal to the speed at which its velocity varies over time, according to Newton's second law in its original formulation.
The block has no acceleration because it is being pushed at a constant speed. If there is no acceleration, there is no force net because the formula is net force =mass × acceleration.
To know more about Force:
https://brainly.com/question/13191643
#SPJ3
Which of these is used to find the estimated age range of a fossil? Group of answer choices Absolute dating Half-life Index fossils Radioactive dating
Answer:
Radioactive Dating
Explanation:
To get the age range of rocks or fossils, researchers usually make use of radiometric dating technique which is also called radioactive dating. Now, this radioactive dating is based on the principle of comparison between the abundance that's observed from a naturally occurring radioactive isotope including its decay products, with the use of known decay rates.
A sprinter runs at a forward velocity of 8.94 m/s. If the sprinter has a mass of 62.4 kg, what is the sprinter's kinetic energy?
1. 2500 J
2. 249 J
3. 249.3 J
4. 2490 J
Plzzz help me!!!
Answer: 2490 J
Explanation:
The formula to calculate kinetic energy is 1/2mv² where,
m = mass = 62.4
v = velocity = 8.94
Kinetic energy = 1/2mv²
= 1/2 × 62.4 × 8.94²
= 1/2 × 62.4 × 79.9236
= 2493.6J
The closest answer is option D.
6. What charge is in the nucleus?
a. negative charge
b. positive charge
C. no charge
d. positive and negative charges
wooden block has a mass of 0.2 kg, has a specific heat of 710 J/(kg°C), and is a temperature of 20.0°C.
What is the block’s final temperature if its thermal energy increases by 2130 J?
Answer:
The final temperature is 35 °C.
Explanation:
Given that,
Mass of the wooden block, m = 0.2 kg
The specific heat of the block, c = 710 J/(kg°C)
Initial temperature, [tex]T_i=20^{\circ} C[/tex]
Thermal energy, Q = 2130 J
We need to find the block's final temperature. The thermal energy due to change in temperature is given by :
[tex]Q=mc(T_f-T_i)\\\\T_i\ \text{is initial temperature}\\\\\dfrac{Q}{mc}=(T_f-T_i)\\\\T_f=\dfrac{Q}{mc}+T_i\\\\T_f=\dfrac{2130}{0.2\times 710 }+20\\\\T_f=35^{\circ} C[/tex]
So, the final temperature is 35 °C.
a ball is thrown vertically upwards from the ground. The ball rises and falls back to the ground. Describe the changes in the mechanical energy of the ball as it rises.
Answer:
as the ball is thrown, the enegry rises up, when it falls, the ball relseases all energy
Explanation:
current is a ______ quantity.
scalar or vector
Answer:
vector quantity............
Explanation:
Mark me braimlist
Answer:
scalar
Explanation:
Sam scored 98, 25, 105, 62 and 65 runs in 5 matches. What was the average score per match?
Answer:
71
Explanation: