Answer:
Magnets work by using Earth's magnetic pull.
Explanation:
Magnets move objects because they are made of steel or metal. And for that reason, they can stick to objects that are metal.
Is work being done on a barbell when a weight lifter is holding the barbell
over his head?
Answer:
Because in order for work to be done on an object, the object must be moving. Why isn't work being done on a barbell when a weight lifter is holding the barbell over his head? Work is maximized when force is applied in the same direction that the object is moving. ... In order to do work faster, more_is required.
A person walks 6.0 miles in 2.5 hours. Calculate the average velocity of the person.
Please show the work and the answer ty.
Answer:
[tex]1.1 \: \mathrm{m/s}[/tex]
Explanation:
The formula for average velocity is [tex]\frac{\Delta x}{\Delta t}[/tex], where [tex]\Delta x[/tex] = total displacement and [tex]\Delta t[/tex] = time.
Because velocity is usually given in meters per second, convert 6.0 miles to meters and 2.5 hours to seconds:
6.0 miles = [tex]9656.09\: \mathrm{meters}[/tex]
2.5 hours = [tex]9000 \: \mathrm{seconds}[/tex]
Therefore the average velocity of the person is [tex]\frac{9656.09}{9000} \approx 1.07 = \fbox{$1.1\: \mathrm{m/s}$}[/tex] (two significant figures).
Hello, what does the first condition mean?
Answer:
An object at rest is described by Newton's First Law of Motion. An object in static equilibrium has zero net force acting upon it. The First Condition of Equilibrium is that the vector sum of all the forces acting on a body vanishes.
Explanation:
Answer:
see below
Explanation:
the first condition means that the light ray inside the optically denser medium hits the surface of the optically less dense medium.
this in simple words means, light must be travelling from am optically denser medium to an optically less dense medium
hope this helps :)
my friend wore a smart watch to bed,when he woke up in the morning it showed 300 steps taken how did this happen?
Answer:
Your tracker will detect your arm movement and will interpret it as steps so this is what it likely happening. Something similar happens while driving, if you go through a bumpy road or your car has a stiff suspension then this can cause the tracker to detect movement and count it as steps. Usually while driving and if you notice some vibration on your car or steering wheel you can try having your tracker a little bit more tight around your wrist and this will help decrease the amount of steps detected.
Explanation:
(Via AlvaroFitbit)
Which of the following is BOTH an isotope and ion of Chlorine? plz help
a
B
c
D
Answer:
The answer is C.
Explanation:
because if you look ay the nutrons you can see that it adds to the protons
Answer:
C
Explanation:
Isotopes of Chlorine (Cl) gain an electron when they form ionic bonds. This results in a negative ion (the Chloride ion). ... When the charge on an atom is zero it means the number of protons is equal to the number of electrons. The atom is said to be neutral and there will not be a + or - written after the element symbol.
Calculate the temperature change when 1000J of heat is supplied to 100g of water.
Please explain
Explanation:
Given
heat supplied (Q) = 1000 J
mass(m) = 100 g = 0.1 kg
specific heat capacity of water(s) = 4200 J/kg°C
change in Temperature (dt) = ?
We know we have the relation
Q = m * s * dt
Or, 1000 = 0.1 * 4200 * dt
Or, 1000 = 420 dt
Or, dt = 1000/ 420
Therefore dt = 2.38°
Hope it will help :)
The temperature changes when 1000J of heat is supplied to 100g of water is dt = 2.38°
What is temperature?The average kinetic energy of a system is measured by its temperature. The kinetic energy of a system starts to rise as the particle's velocity increases, which raises the system's temperature.
The energy that is transferred when two bodies with different surface temperatures come in touch is referred to as heat.
The change is when 1000J of heat is supplied to 100g of water.
Given that:
heat supplied (Q) = 1000 J
mass(m) = 100 g = 0.1 kg
specific heat capacity of water(s) = 4200 J/kg°C
Change in Temperature (dt) = ?
We know we have the relation
Q = m x s x dt
Or, 1000 = 0.1 x 4200 x dt
Or, 1000 = 420 dt
Or, dt = 1000/ 420
Therefore, the temperature changes when 1000J of heat is supplied to 100g of water is dt = 2.38°.
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5
A cyclist travels 125 km in 5 hours. How fast is the cyclist moving?
Answer:
25 km/h
Explanation:
speed=distance÷time
125÷5=speed
125÷5=25 (then add units)
A solar panel gives our 250 Watts
of power in 2 seconds. How much
work did the solar panel do?
Jack and Jill decide to run a race. Jack weighs 90 kg and Jill weighs 50 kg. At the end of the race it was decided that Jack and Jill tied so they had the same speed. Which person had more momentum ?
Answer: Jack.
Explanation:
Momentum is defined as the quantity of motion.
For an object that has a mass M, and a velocity V, the momentum is written as:
P = M*V
For this problem, we know that Jack and Jill had the same speed (so they had the same velocity), let's say that this velocity is v.
Then the momentum of Jack will be:
P = 90kg*v
And the momentum of Jill will be:
P = 50kg*v
We can see that Jack will have a larger momentum, and this is because he has a larger mass than Jill, but the same velocity as her.
Compare between Convex lens and concave lens
Answer:
A convex lens or converging lens focuses the light rays to a specific point whereas a concave lens or diverging lens diverges the light rays. When these lenses are combined, they produce sharper images. Most of the eyeglass lenses use combinations of convex and concave lenses.
The Periodic Table Question 4 of 10 If an element forms a 2+ ion, in which group of the periodic table would you expect to find it? D A. 2 B. 17 O C. 1 D. 18 7
Answer:
B is the difference قصدي لا انا اعرف بشير بس ما اعرف اخوه يعني *قصدي لا انا اعرف بشير بس ما اعرف اخوه يعني *قصدي لا انا اعرف بشير بس ما اعرف اخوه يعني *قصدي لا انا اعرف بشير بس ما اعرف اخوه يعني *قصدي لا انا اعرف بشير بس ما اعرف اخوه يعني *
A force of 2 kN is applied to an object to make it move 3.6 m in the direction of the force. Select the correct value of work done on the object.
Answers to choose from:
1.8J
7200J
7.2J
555.6J
Answer:
W= F × d
W= 2kn × 3.6
W= 7.2 J
Work is measured in Joules!
MY BRAINS NOT WORKING
Describe how Newton's Third Law applies to the forces between the bike and
the trailer.
Answer:
Explanation:
The Earth pulls the bicycle downward through the force of gravity, and, in response, the bicycle pulls up on the Earth with a force of equal magnitude. Gravity "pushes" the Earth into the road, which pushes up with an opposite force, canceling gravity. Thus, action reaction forces do not cancel each other.
HELLLPPPPPPPPPPPPPPPPPP
Answer:
If you going to ask a question ask it accurately.
Explanation:
A dog starts at the origin and runs forward at 6m/s for 1.5s and then turns around to fetch the ball by running backward at 7m/s for 3s. If the dog runs back to the origin at 4m/s the how much time has elapsed between the start and when he returns with the ball
Answer:
Total time elapsed between the start and when he returns with the ball is 7.5s
Explanation:
From the question,
- The dog starts at the origin and runs forward at 6m/s for 1.5s. First, we will determine the distance covered while running forward.
From
Speed = Distance / Time
Distance = Speed × Time
Speed = 6m/s
Time = 1.5s
∴ Distance = 6m/s × 1.5s
Distance = 9m
That is, the dog covered a distance of 9m while running forward.
- The dog turns around and runs backward at 7m/s for 3s. Now, we will also determine the distance the dog covered backwards.
Distance = Speed × Time
Speed = 7m/s
Time = 3s
Distance = 7m/s × 3s
Distance = 21m
The dog's displacement from the origin is 21m - 9m = 12m
Now, to calculate how much time has elapsed between the start if the dog runs back to the origin at 4m/s, we will first determine the time the dog spent back to the origin and then add to the time spent for the first two distances.
To get back to the origin, the dog needs to cover 12m
From
Speed = Distance / Time
Time = Distance / Speed
Distance = 12m
Speed = 4m/s
∴ Time = (12m) / (4m/s)
Time = 3s
Therefore, the dog spent 3s to run back to the origin.
Hence, total time elapsed = 1.5s + 3s + 3s
Total time elapsed = 7.5s
An 69-kg jogger is heading due east at a speed of 1.6 m/s. A 63-kg jogger is heading 14 ° north of east at a speed of 1.5 m/s. Find (a) the magnitude and (b) the direction of the sum of the momenta of the two joggers. Describe the direction as an angle with respect to due east.
Answer:
[tex]P=203.3819375kg.m/s\\P\approx203.4kg.m/s[/tex]
[tex]\theta=6.4541\textdegree North East\\\theta\approx6.5\textdegree North East[/tex]
Explanation:
From the question we are told that
Mass of first jogger [tex]M=69kg[/tex]
Speed[tex]v_1=1.6m/s[/tex]
Direction [tex]d= East[/tex]
Mass of 2nd jogger [tex]M=63kg[/tex]
Speed [tex]v_2=1.5m/s[/tex]
Direction [tex]d= 14\textdegree north[/tex]
Generally equation for momentum along the the horizontal is mathematically given as
[tex]P_x=m_1v_1 +m_2v_2cos\theta[/tex]
[tex]P_x=(69)*(1.6) +(63)*(1.5)cos14[/tex]
[tex]P_x=202.0929461kg.m/s[/tex]
Generally equation for momentum along the the vertical is mathematically given as
[tex]P_y=m_2v_2cos\theta[/tex]
[tex]P_x=22.86161913kgm/s[/tex]
a)Generally the magnitude of momentum is mathematically given by
[tex]P=\sqrt{(P_x)^2+(P_y)^2}[/tex]
[tex]P=\sqrt{(202.0929461)^2+(22.86161913)^2}[/tex]
[tex]P=\sqrt{41364.21249}[/tex]
[tex]P=203.3819375kg.m/s[/tex]
[tex]P\approx203.4kg.m/s[/tex]
b) Generally the angle [tex]\theta[/tex] is mathematically given by
[tex]\theta=tan^-^1\frac{py}{px} \\[/tex]
[tex]\theta=tan^-^1\frac{22.86161913}{202.0929461}[/tex]
[tex]\theta=tan^-^1(0.1131242805)[/tex]
[tex]\theta=6.4541\textdegree North East[/tex]
what happens if I increase the height of a skater
Answer:
The higher the skater is the more potential energy he has. As his height decreases, his potential energy decreases and his kinetic energy increases.
Explanation:
Make me BRAINLIST please
Answer:
The higher the skater is the more potential energy he has. As his height decreases, his potential energy decreases, and his kinetic energy increases. ... Explore how the skater's change in speed relates to the potential and kinetic energy of the skater.
Explanation:
(Via Uteach)
How much potassium nitrate (KNO3) would dissolve in 50 milliliters of water at 45ºC given that 55g of KNO3 is dissolved in 150mL of water at 45°C.
A. 19.7g
B. 15.1g
C. 18.3g
D. 23.3g
Jeff throws a ball straight up. For which situation is the vertical velocity zero?
a. on the way up
b. at the top
c. on the way back down
d. none of the above
Answer:
b. at the top
Explanation:
At the top of the climb, the vertical velocity of Jeff's throw has a value of zero.
Vertical velocity in this instance is acting against the acceleration due to gravity.
At the top of the thrown, the force of the throw becomes zero and the velocity also becomes zero. As the body finds it way downward, it begins to fall freely. The fall is due to the acceleration due to gravity which is experienced by every object on earth.Why does Farm Bureau and other advocacy organization oppose any mandated labeling of biotech crops?
Answer:
I’m. Nog sure
Explanation:
Look at the atoms below
a. Atom W: 9 protons and 9 neutrons
b. Atom X: 8 protons and 9 neutrons
c. Atom Y: 9 protons and 9 neutrons
d. Atom Z: 9 protons and 10 neutrons
Which ones below are isotopes of each other and why?
element z are isotopes because number of netron are different and number of protons are same
(97-R) Dos cargas puntuales iguales están separadas por una distancia d. A) ¿Es nulo el campo eléctrico total en algún punto? Si es así, ¿cuál es la posición de dicho punto? B) Repita el apartado anterior suponiendo que las cargas fueran de distinto signo.
Answer:
Explanation:
El campo eléctrico provocado por una carga puntal sobre determinado punto viene dado por la ecuación:
E = K * Q /r² en esa ecuación E es el campo eléctrico (un vector), K es una constante K = 1/4*π*ε₀ Q es la carga que origina el campo, y r la distancia entre la carga y el punto donde se quiere determinar el campo. La fuerza de origen eléctrico y el campo eléctrico van en la dirección de la recta de unión entre carga y punto ( es decir según r) y esta fuerza sera repulsiva o de atracción según que la carga que la origina sea positiva o negativa (respectivamente, ya que en la determinación de fuerza y campo, se asume que se coloca una carga de prueba positiva en el punto ).
Siendo así, si dos cargas elécticas son iguales y están separadas una distancia r ; en el punto medio (r/2) los campos producidos por cada una de las cargas serán de la misma magntud.
Carga Q₁ = Carga Q₂ = Q
E₁ = K * Q₁ / (r/2)² y E₂ = K * Q₂/(r/2)²
Y además tendran direcciones totalmente opuestas, por lo que se anularan
En el segundo caso las cargas son iguales en magntud pero de diferentes signos ( una positiva y la otra negativa ). En este caso los campos eléctricos continuaran siendo de la msma magnitud pero dado que la carga positiva repele la carga de muestra (teorica) y la negativa la atrae los dos campos coinciden en su dirección y resultará una campo de magnitud doble. La dirección del campo será en la tendencia de acercarse a la caga negativa, así si la carga negativa está a la derecha la fuerza de origen eléctrico y el campo van hacia la derecha y si la carga negativa está a la izquierda pues esa será la diercción del campo
2) Ariel dropped a golf ball from her second story window. The ball starts from rest and hits the sidewalk 1.5 s later with a velocity of 14.7 m/s. Find the average acceleration of the golf ball.1.5x14.7 =22.05
Answer:
Acceleration = 9.8m/s²
Explanation:
Given the following data;
Initial velocity = 0m/s (since it's starting from rest).
Final velocity, v = 14.7m/s
Time, t = 1.5 seconds.
To find acceleration;
In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.
This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.
Hence, if we subtract the initial velocity from the final velocity and divide that by the time, we can calculate an object’s acceleration.
Mathematically, acceleration is given by the equation;
[tex]Acceleration (a) = \frac{final \; velocity - initial \; velocity}{time}[/tex]
[tex]Acceleration = \frac{v - u}{t}[/tex]
Substituting into the equation, we have;
[tex]Acceleration = \frac{14.7 - 0}{1.5}[/tex]
[tex]Acceleration = \frac{14.7}{1.5}[/tex]
Acceleration = 9.8m/s²
Therefore, the average acceleration of the golf ball is 9.8m/s².
1. How much heat must be absorbed by 375 grams of water to raise its
temperature by 25° C?(Cp of water is 4.184)
Answer:
39225J
Explanation:
Given parameters:
Mass of water = 375grams of water
Change in temperature = 25°C
Specific heat capacity of water = 4.184J/g°C
Unknown:
Amount of heat absorbed = ?
Solution:
To solve this problem, we use the expression below:
H = m c Ф
H is the heat absorbed
m is the mass
c is the specific heat capacity
Ф is the change in temperature
Insert the parameters and solve;
H = 375 x 4.184 x (25) = 39225J
What state of matter can easily be compressed (squeezed into a much smaller space)? *
gases
solids
solids, liquids, and gases
liquids
Answer:
gases.
Explanation:
gases have the highest volume. if you compress (increase pressure) a gas, the volume decreases and it will take up less space as a liquid, and if you compress more, the liquid will become a solid.
additionally info: this is generally true, but as you get into more difficult subjects, this rule does not hold. for example, some substances cannot obtain a certain phase of matter when they are a certain temperature and or pressure. but that could be way more out of this questions league.
A friend tells you that objects with more mass fall faster because they
have a stronger gravitational pull to Earth. How can you show your friend
that this is not true?
Answer:
by throwing heavy mass and less mass in vacuum simultaneously.
HELP PLEASE!
A 700 kg race car makes one lap around a track. It has a velocity of 20 m/s with a centripetal force of 5,600 N. What is the radius of the track?
A speed skater goes around a turn with a 25 m radius. The skater has a velocity of 15 m/s and experiences a centripetal force of 720 N. What is the mass of the skater?
A 900-kg car moving at 5 m/s takes a turn around a circle with a radius of 30 m. Determine the net force acting upon the car.
An 800 kg race car makes one lap around a track. It has a velocity of 40 m/s with a centripetal force of 16,000 N. What is the radius of the track?
PLEASE EXPLAIN AND SHOW WORK!
The centripetal force is the force that keeps a body moving in a circular path.
The centripetal force is given by; F = mv^2/r
1) We have;
F = 5,600 N
v = 20 m/s
r =?
m = 700 kg
Making r the subject of the formula;
r =mv^2/F
r = 700 × (20)^2/5,600
r = 50 m
2) F = mv^2/r
F = 900 × (5)^2/30
F = 750 N
3) Making r the subject of the formula;
r =mv^2/F
r = 800 × (40)^2/ 16,000
r = 80 m
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Starting from rest, a sprinter reaches his top velocity in 3 seconds. He runs a distance of 24m in 3 seconds. What is his acceleration? (Assume his acceleration is uniform)
Answer:
[tex]a=5.34\ m/s^2[/tex]
Explanation:
Given that,
Initial velocity of a sprinter, u = 0
He runs a distance of 24m in 3 seconds.
We need to find his acceleration. Let a be his acceleration. Using second equation of kinematics to find it.
[tex]s=ut+\dfrac{1}{2}at^2\\\\24=0+\dfrac{1}{2}a(3)^2\\\\a=\dfrac{24\times 2}{9}\\\\a=5.34\ m/s^2[/tex]
So, the acceleration of the sprinter is [tex]5.34\ m/s^2[/tex].
The acceleration of the sprinter from rest to his top speed is 5.33m/s²,
Given the data in the question
Since the sprinter starts from rest,
Initial velocity; [tex]u = 0[/tex]Time taken; [tex]t = 3s[/tex]Distance covered; [tex]s = 24m[/tex]Acceleration; [tex]a = \ ?[/tex]
To determine the acceleration of the sprinter, we use the second equation of motion:
[tex]s = ut + \frac{1}{2}at^2[/tex]
Where s is distance covered, u is initial velocity, a is acceleration and t is time.
We substitute our given values into the equation
[tex]24m = [0 * 3s] + [\frac{1}{2} * a * (3s)^2]\\\\24m = \frac{1}{2} * a * 9s^2\\\\24m = a * 4.5s^2\\\\a = \frac{24m}{4.5s^2} \\\\a = 5.33m/s^2[/tex]
Therefore, the acceleration of the sprinter from rest to his top speed is 5.33m/s²
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A flight attendant pulls her 70 N flight bag a distance of 318 m along a level airport floor at a constant velocity. The force she exerts is 41 N at an angle of 57° above the horizontal.
Complete question :
A flight attendant pulls her 70 N flight bag a distance of 318 m along a level airport floor at a constant velocity. The force she exerts is 41 N at an angle of 57° above the horizontal.
(a) Find the work she does on the flight bag.
(b) Find the work done by the force of friction on the flight bag.
(c) Find the coefficient of kinetic friction between the flight bag and the floor.
Answer:
7107 J ; - 7107 J ; 0.55
Explanation:
Given that :
Distance, d = 318m
Applied force = 41 N
θ = 57°
A.) Workdone = Force exerted along direction of motion
Workdone = applied Force * distance * cosθ
Workdone = 41 * 318 * cos57 = 7101.0037
Workdone = 7,101 J
B.) Workdone by force of friction on flight bag:
- 7,101 J (since the body moves at constant velocity)
C.)
Coefficient of kinetic friction (μ) = Frictional force / normal reaction)
μ = F / N
Frictional force, F = Workdone by friction / distance
F = 6200 / 318
F = 19.47N ;
Ff = weight of Flight bag = 70 N
N = Ff - Fsinθ
N = 70 - applied Force sinθ
N = 70 - 41sin57
N = 70 - 34.385493
N = 35.614506
μ = 19.47 / 35.614506
μ = 0.5466873
A piece of glass weights 25 g in air, 16.77g in water at 4C and 16.89g in water at 60C. Find the mean coefficient of cubical expansion of water between 4C anf 60C, taking the coefficient of linear expansion of glass as 8*10^6
sorry i think so i dont exactly know i am sorry
Explanation:
As a certain amount of water is cooled from room temperature until it reaches 4 °C, its volume drops. The density reduces as the volume increases below 4 °C. Therefore, water's greatest density occurs at 4 degrees Celsius.
What coefficient of cubical expansion of water?Water has an unusual trait called anomalous expansion, which causes it to enlarge rather than compress when the temperature drops from 4 °C to 0 °C, and it becomes less dense.
At temperatures not far below zero degrees Celsius, water ice is unique for having low coefficients of static and dynamic friction that range from 0.04-0.02, but as the temperature drops, these numbers rise.
Therefore, When a metal sheet's temperature rises by one degree, its coefficient of area expansion is calculated as the increase in surface area per unit of original surface area.
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