Answer:
Metals
plz mark as brainliest
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
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 car traveled 1,215 km West from El Paso to Dallas in 13.5 hours. What was its velocity?
A. 90m/s West
B. 90km/h
C. .09km/h West
D. 90km/h West
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.
How many Joules of energy are required to make 50 kg of ice completely melt?
Hv = 226,000 J/kg
Hf = 334,000 J/kg
Answer:
In order to answer this question, you need the enthalpy of fusion of ice, which is 333.55 J/g (Joules/gram). The enthalpy of fusion is the amount of heat that must be absorbed or lost in order to change physical state.
The number of Joules required to melt the ice = enthalpy of fusion of ice x mass of ice.
1 kg = 1000g
40kg x (1000g/1kg) = 40,000g
Joules needed to melt the ice = 333.55 J/g x 40000 g = 13342000 J or
1.3342 x 107 J
Explanation:
Instead of 40kg input 50kg and get the answer
"Energy is never created of destroyed, it only transforms from one form to another" is the definition of… A. The Law of Diminishing Returns B. The Law of Conservation of Energy C. The Law of Universal Gravitation D. The Law of Entropy
Answer:
B. The Law of Conservation of Energy
Explanation:
In Science, energy can be defined as the ability of an object or body to do work. There are two (2) main types of energy and these are;
I. Kinetic energy: it can be defined as an energy possessed by an object or body due to its motion.
Mathematically, kinetic energy is given by the formula;
Where, K.E represents kinetic energy measured in Joules.
M represents mass measured in kilograms.
V represents velocity measured in metres per seconds square.
II. Potential energy: it can be defined as an energy possessed by an object or body due to its position.
Mathematically, potential energy is given by the formula;
Where, P.E represents potential energy measured in Joules.
m represents the mass of an object.
g represents acceleration due to gravity measured in meters per seconds square.
h represents the height measured in meters.
Additionally, the various forms of energy are solar energy, electrical energy, chemical energy, thermal energy, wind energy, nuclear energy etc.
Hence, energy is never created of destroyed, it only transforms from one form to another" is the definition of The Law of Conservation of Energy.
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°.
To learn more about temperature, refer to the link:
https://brainly.com/question/11464844
#SPJ2
Explain why refraction takes place.
Please help explain in a simple way
Answer:
lCdfKFBWRblNLWFNJLBe
Explanation:
jk jk Refraction is an effect that occurs when a light wave, incident at an angle away from the normal, passes a boundary from one medium into another in which there is a change in velocity of the light
Why does Farm Bureau and other advocacy organization oppose any mandated labeling of biotech crops?
Answer:
I’m. Nog sure
Explanation:
which property of a conducting wire is utilised in making electric fuse
Answer:
property of low melting point
Explanation:
When too much current flows through the low resistance element of the fuse, the element melts and breaks the circuit
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.
If a 1-N net force accelerates a l-kg mass at Im/s2, what is the acceleration caused by a net force of 2 N on a 2-kg mass?
Answer:
The acceleration caused by a net force of 2 N on a 2 kg mass is 1 m/s²
Explanation:
The given parameters on an applied force is as follows;
The acceleration given to a 1 kg mass by a 1-N net force = 1 m/s²
According to Newton's second law of motion, the acceleration, "a", given to an object by a force, "F", is proportional to the magnitude of the net force
Therefore, we have;
F ∝ a
The constant of proportionality is given as the mass, "m", of the object, therefore, we have;
F = m × a
The acceleration given to a 2 kg mass by a 2-N net force is given therefore, given as follows;
2 N = 2 kg × a
a = 2 N/(2 kg) = 1 m/s²
The acceleration, "a", caused by a net force of 2 N on a 2 kg mass is a = 1 m/s².
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.
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.
You weigh 620 N. What would you weigh if the Earth were three times as massive as it is and its radius were four times its present value? Answer in units of N
Answer:
if
Explanation:
weight is the force of gravity on a mass; the force of gravity is
F = G M m/r^2
F is grav force
G is the newtonian gravitational constant = 6.67 x 10^-11 Nm^2/kg^2
M=mass of the earth
m=mass of the object
r= radius of the earth
if the mass of the earth increases by a factor of 6, this will tend to increase the grav force by a factor of 6
if the radius increases by a factor of 5, this will change the grav force by a factor of 1/5^2 = 1/25
the total effect is 6/25 = 0.24; therefore, your weight would be 0.24 * 620N = 149N
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.How are CD's recorded?
Using digital technology
using analog technology
Answer:
its digital technology
HELLLPPPPPPPPPPPPPPPPPP
Answer:
If you going to ask a question ask it accurately.
Explanation:
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
Learn more: https://brainly.com/question/18835025
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.
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 :)
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).
Who was the most famous member of the Underground Railroad?
Answer:
Harriet Tubman
Explanation:
Answer:
Harriet Tubman
Explanation:
She was an abolitionist and fought for women's rights.
Harriet was also the first woman to lead a combat assault.
If an atom gains a neutron, what happens to the atom?
Answer:
If an atom gains a neutron, the atom becomes an isotope, which means that it has the same atomic number (#of protons) but a different atomic mass because it has gained the mass of 1 neutron
a train has an initial velocity of 44m/s and an accelaration of _4m/s calculate its velocity
Complete question:
A train has an initial velocity of 44m/s and an acceleration of -4m/s². calculate its velocity after 10s ?
Answer:
the final velocity of the train is 4 m/s.
Explanation:
Given;
initial velocity of the train, u = 44 m/s
acceleration of the train, a = -4m/s² (the negative sign shows that the train is decelerating)
time of motion, t = 10 s
let the final velocity of the train = v
The final velocity of the train is calculated using the following kinematic equation;
v = u + at
v = 44 + (-4 x 10)
v = 44 - 40
v = 4 m/s
Therefore, the final velocity of the train is 4 m/s.
A person trapped outside during a thunderstorm should
Answer:
should stay away from trees, water, and tall objects.
Answer: the answer is
stay away from trees, water, and tall objects.:)Explanation:
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!
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)
(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
A cell of e.m.f 1.5 v and internal resistance 2.5 ohm is connected in series with an ammeter of resistance 0.5 ohm and a resistor of resistance 7.0 ohm. Calculate the current in the circuit.
Answer:
The current in the circuit is 0.15 Ampere
Explanation:
The given parameters of the cell are;
The electromotive force (e.m.f.) of the cell, E = 1.5 V
The resistance of the cell, r = 2.5 ohm
The resistance of the ammeter = 0.5 ohm
The resistance of the resistor = 7.0 ohm
The formula for the e.m.f., E of a cell is given as follows;
e.m.f. E = I·(R + r)
Where;
I = The current in the circuit
R = The sum of the resistances in the circuit = 7.0 Ω + 0.5 Ω + 2.5 Ω = 10 Ω
Therefore, we have;
[tex]The \ current \ in \ the \ circuit, \ I = \dfrac{E}{R + r}[/tex]
Substituting the known values, gives;
[tex]I = \dfrac{1.5 \ V}{7 \ \Omega + 0.5 \ \Omega + 2.5 \ \Omega} = \dfrac{1.5 \ V}{10 \ \Omega} = 0.15 \ A[/tex]
The current in the circuit, I = 0.15 Ampere.
