Answer:
answer 2 because the baseball has less mass then the 1st one
A 55 kg roller skater is at rest on a flat skating rink, a 198 N horizontal force is needed to set the skater in motion.
However, after the skater is in motion a horizontal force of 175 N is necessary to overcome the friction of 52N to keep
the skater moving at a constant velocity. Find the coefficient of kinetic friction.
Answer:
Explanation:
To get the person Moving you have to overcome the static (means not moving) friction coefficient. U(static)
To get the person going at the same speed you have to overcome the kinetic friction coefficient. U(Kinetic)
Force to get him moving is 198 N. Force = ma = U(static)Mg
combining the 2 equations you get 198N = U(static)* 55kg *9.8m/s^2 Solve for U(static)
Same equation to keep him moving except with the dynamic force and the dynamic U
175N= U(kinetic)*55kg*9.8m/s^2 Solve (U dynamic)
Newton's second law and the expression of the friction force allow to find the result for the value of the kinetic friction coefficient is:
μ = 0.325
Newton's second law establishes a relationship between the net force, mass, and acceleration of the body.
Σ F = m a
Where the bold letters indicate vectors, m is the mass and the acceleration.
The friction force is a macroscopic force that represents the interactions between the two surfaces, it can be of two types:
Static. If there is no relative movement between the two surfaces. Kinetics. If there is relative movement between the two surfaces.The expression in both cases is:
fr = μ N
Where N is the normal and μ is the friction coefficient, one value for the static case and another for the kinetic case.
In the attachment we have a free-body diagram for when the skater is moving with constant speed.
y=axis
N - W = 0
N = W
x-axis
F - fr = 0
F = fr
They indicate that the applied force is F = 175N and the mass of the skater is m = 55 kg.
We substitute.
F = μ mg
μ = [tex]\frac{F}{mg}[/tex]
Let's calculate.
μ =[tex]\frac{175}{55 \ 9.8}[/tex] 175/55 9.8
μ = 0.32
In conclusion, using Newton's second law and the expression of the friction force we can find the result for the value of the coefficient of kinetic friction is:
μ = 0.325
Learn more here: brainly.com/question/1714663
Someone please help me
What is an isotope? (2 points)
Group of answer choices
Atoms of different elements that have different numbers of neutrons
Atoms of different elements that have different numbers of protons
Atoms of the same element that have different numbers of neutrons
Atoms of the same element that have different numbers of protons
Answer:
The answer is C.) Atoms of the same element that have different numbers of neutrons.
Explanation:
I know this is right because i took the test!
Calculate the magnitude and direction of a vector whose x and y components are given
to be 30 and 40 units respectively.
Answer:
Magnitude = 50 units
Direction = 53.13°
Explanation:
The formula to find out the magnitude of a resultant vector with the help of its x and y components is given as follows:
[tex]Magnitude = \sqrt{x^{2} + y^{2}}\\\\[/tex]
where,
x = 30 units
y = 40 units
Therefore,
[tex]Magnitude = \sqrt{(30 unit)^{2} + (40\ unit)^{2}}\\\\[/tex]
Magnitude = 50 units
Now, the direction of the resultant vector will be given by the following formula:
[tex]Direction = tan^{-1}\frac{y}{x}\\\\Direction = tan^{-1}\frac{40}{30}[/tex]
Direction = 53.13°
WILL REWARD ASAP Calculate the density of a 25g stone that causes water in a graduated cylinder to
go up by 12.5 ml.
What happens when you call someone using your cell phone?
A. Microwaves travel from your cell phone directly to the cell phone
of the person you are calling.
B. Microwaves reach a cell tower, then fiber optic cables send the
signal to a cell tower near the person you are calling.
C. A system of satellites orbiting Earth receives the microwave
signals and sends them to the person you are calling.
D. Sound waves reach a cell tower, then fiber optic cables send the
signal to a cell tower near the person you are calling.
Answer: B, Microwaves reach a cell tower, then fiber optic cables send the signal to a cell tower near the person you are calling.
Explanation:
Answer:D. Sound waves reach a cell tower, then fiber optic cables send the
signal to a cell tower near the person you are calling.
Explanation: just got it right
Please help, quicklyyyyy
A 1.0 kg ball is thrown into the air with an initial velocity of 30 m/s. What is the kinetic energy of the ball?
Answer:
If this helps, to work out the kinetic energy the formula is K (stands for kinetic energy) = 1/2 (half of) mass and velocity. So the answer is 450 joules.
Explanation:
a carbon atom with 6 proton and 6 neutron in its nucleus is called carbon-12 the carbon atom with 8 neutrons is called what
Answer:
carbon-14 must be the answer
A hollow glass prism doesnot cause the dispersion of light why?
Please HELP! Its urgent..
Answer:
When white light passes through the prism ,different colours suffers deviation through different angles and light appears to be dispersed. But in a hollow prism dispersion does not take place as all the colours travel with same speed in the air inside hollow prism. Thus no angular dispersion is there.
when a person holds a ball above earth's surface, where is this potential energy stored?
Answer:
in the ball
Explanation:
potential energy is where an object has energy, always, but it isn't always moving, and when you drop the ball, it has kinetic energy.
help me please!!!!!..............
Answer:
The car took 3 hours to travel 180 miles
Explanation:
Constant Speed Motion
An object travels at constant speed if the ratio of the distance traveled by the time taken is constant.
Expressed in a simple equation, we have:
[tex]\displaystyle v=\frac{d}{t}[/tex]
Where
v = Speed of the object
d = Distance traveled
t = Time taken to travel d.
From the equation above, we can solve for t:
[tex]\displaystyle t=\frac{d}{v}[/tex]
The car travels at v=60 mi/h for a distance of d=180 miles. The time taken is:
[tex]\displaystyle t=\frac{180\ mi}{60\ mi/h}[/tex]
t = 3 hours
The car took 3 hours to travel 180 miles
The stone, which weighs 400 g, is thrown upwards at a speed of 20 m / s. Climbed to a height of 12 m. Determine: what is equal to the work of the resistance force; equal to the mean resistance force?
Given that,
Mass of the stone, m = 400 g = 0.4 kg
Initial speed, u = 20 m/s
It is climbed to a height of 12 m.
To find,
The work done by the resistance force.
Solution,
Let v is the final speed. It can be calculated by using the conservation of energy.
[tex]v=\sqrt{2gh} \\\\v=\sqrt{2\times 9.8\times 12} \\\\v=15.33\ m/s[/tex]
Work done is equal to the change in kinetic energy. It can be given as follows :
[tex]W=\dfrac{1}{2}m(v^2-u^2)\\\\=\dfrac{1}{2}\times 0.4\times (15.33^2-20^2)\\\\=-32.99\ J[/tex]
So, the required work done is 32.99 J.
Comparing the reactants and the products of a chemical reaction, which observation can best be used to argue that the reaction is endothermic?(1 point)
The volume of the reactants is greater than the volume of the products.
The total energy of the reactants is equal to the total energy of the products.
There are fewer chemical bonds in the reactants than there are chemical bonds in the products.
The temperature of the reactants is greater than the temperature of the products.
Answer:
D) The temperature of the reactants is greater than the temperature of the products.
Explanation:
All the answers:
1. A) The reactants are unlit charcoal, and the products are charcoal that has already burned and released its energy
2. C) sugar + oxygen → carbon dioxide + water + energy
3. D) iron + oxygen → rusted iron + energy
4. A) an endothermic reaction, because ice absorbs heat to become liquid water
5. D) The temperature of the reactants is greater than the temperature of the products.
We can argue that a reaction is endothermic when the temperature of the reactants is greater than the temperature of the products.
What is an endothermic reaction?An endothermic reaction is a chemical reaction accompanied by the absorption of heat.
Comparing the reactants and the products of a chemical reaction, which observation can best be used to argue that the reaction is endothermic?
The volume of the reactants is greater than the volume of the products. False. There is no relation between the volume and the endothermicity.The total energy of the reactants is equal to the total energy of the products. False. If the total energy is equal, there is no heat (energy) absorption.There are fewer chemical bonds in the reactants than there are chemical bonds in the products. False. We must consider not only the number of bonds, but also their energies, to establish if a reaction is endothermic.The temperature of the reactants is greater than the temperature of the products. True. If the reaction is endothermic and absorbs heat from the surroundings, the temperature of the reactants will be greater than the temperature of the products.We can argue that a reaction is endothermic when the temperature of the reactants is greater than the temperature of the products.
Learn more about endothermic reactions here: https://brainly.com/question/1995950
Pollen grains help scientists
identify plants and make assumptions on past climate conditions.
understand tree growth and make assumptions on past climate conditions.
understand how Earth was shaped and make assumptions on past climate conditions.
identify major ice ages and make assumptions on past climate conditions.
Answer:
A. identify plants and make assumptions on past climate conditions.
Explanation:
Answer was right on my Edge quiz!
Pollen grains help scientists identify plants and make assumptions on past climate conditions.
WHAT IS PROXY CLIMATE?Proxy climate is climate inferred from past records i.e. not current.
Proxy climate makes use of proxy climate data also called proxies. These proxies help in inferring about the past climate.
Examples of proxies are;
pollen grainsCoral reefsIce coresTherefore, pollen grains help scientists identify plants and make assumptions on past climate condition.
Learn more about past climate at: https://brainly.com/question/9328022
The answers plz....................
Answer:
The answer would be D
Explanation:
It's quite simple, the Universal Law of Gravitation states that all mass no matter the size, shape, or weight acts equally upon the force of gravity of the gravitational object. Basically, between all sizes, shapes, weights of masses, gravity applies the same gravitational force with all. Gravity with friction would be something else, which is also states in the Theory of Gravitation.
When is the world going to end? Give me your opinions and the reasons why you think that.
Answer:
probably when the next pandemic happens
Which Newton’s law is shown below?
First
Second
Third
Pls answer
Answer:
This is Newton's first law.
Explanation:
An object in motion will stay in motion and an object at rest wI'll stay at rest unless acted upon by an unbalanced force.
A boy is pulling a box on the ground by a string to the right. What four forces he using?
help with this pleaseeee i’ll give brainlist:)
Answer:
C. Test to see if your material is strong and works well.
can a plane mirror firm a real image ? if yes tell me how ?
Answer:
Explanation:
A plane mirror will produce a virtual image of a real object. But it is correct that a plane mirror will also produce a real image of a virtual object.A virtual image An image in a mirror is a virtual object, which can in turn be used to create another image. This can occur when you have more than one optical element in the optical system. Then the object of one component becomes the image of the next optical component.
So the answer is Yes it will!!!!
Answer:
I think u know the answer of this question
You are riding a skateboard and hit a hole in the street, causing you to fly off the board and crash. Which law represents this action? *
Answer:
Newton's first law of motion states that an object at rest will remain at rest and an object in motion will remain in motion unless it is acted on by an unbalanced force. Using unbalanced forces to control the motion of a skateboard demonstrates Newton's first law of motion.
Hope it helps
Answer:
Good question! It's the law of motion.
Explanation:
Periodic waves with a wavelength of 0.50 meter move with a speed of 0.30 meter in medium A. When the waves enter medium B, they travel at 0.15 meter per second. Calculate the wavelength of the waves in medium B.
Answer:
0.25 m
Explanation:
Refraction occurs when the velocity or wavelength of a wave changes at the interface between two media.
We know that refractive index=
Wavelength in medium A/wavelength in medium B = velocity in medium A/velocity in medium B
Let the wavelength of medium B be a
0.5/a = 0.3/0.15
0.5 × 0.15 = 0.3 × a
a= 0.5 × 0.15/0.3
a= 0.25 m
What element does the picture represent? (Use the periodic table if you need to) *
(1 Point)
nitrogen
O chlorine
O oxygen
Why is the solar system commonly represented as a scale model?
Please write in complete sentences. I will mark Brainiest to whoever correct.
Witch of these units is NOT used to measure speed? m/s, km/h, mph, km
Answer:
km
Explanation:
Answer:
Km
Explanation:
Speed is measured is distance traveled/time
What units are used to measure mass and weight?
A total charge of 7.5 mC passes through a cross-sectional area of a wire in 0.9 s. What is the current in the wire
Answer:
the current in the wire is 0.008333333 A
Explanation:
The computation of the current in the wire is as follows;
Current in the wire is
= Total charge ÷ cross sectional area of the wire
= 7.5 × 10^-3C ÷ 0.9s
= 0.008333333 A
Hence, the current in the wire is 0.008333333 A
We simply applied the above formula so that the correct current of the wire could come
And, the same is considerd and relevant too
PSYCHOLOGY
The most widely used psychoactive drug is
ОА.
heroin.
B.
caffeine.
O C.
PCP.
O D.
LSD.
the answer is B.caffeine. Just didn’t see anyone have this question on Brainly yet.
d is the right answer
Which statement best defines the resistance of an electric circuit? (1 point) o It limits the amount of electrical energy that can pass through a circuit. 0 It is the measurement of the rate of electrical energy in a circuit. O It is the amount of electrical energy that is available in a circuit. O It describes how much electrical energy passes in a circuit.
Answer:
it limits the amount of electrical energy that can pass through a circuit
A skier is moving at a constant velocity for 20 seconds when he hits a downhill slope of 60 meters and begins to accelerate at 6 m/s^2 for 6 seconds. At the bottom of the hill he begins to stop over 10 seconds
a. What was the skiers constant velocity before going down hill?
b. What was the skier’s acceleration as he comes to a stop?
c. What was the skier’s total distance over the 36 seconds?
d. What was the skier’s average speed during the 36 seconds?