Is work being done on a barbell when a weight lifter is holding the barbell
over his head?

Answer:

Because both monomers and polymers and cross linked polymers are mers with physically properties which is good for applycations

Explanation:

because they are good for using and not using

also, this is a 5 point question, you are not  fooling anyone. thx for 5 points tho

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,

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

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

Answer:

Heat vs temperature - Energy Education The core difference is that heat deals with thermal energy, whereas temperature is more concerned with molecular kinetic energy. Heat is the transfer of thermal energy, whereas temperature is a property the object exhibits.

element z are isotopes because number of netron are different and number of protons are same

The intensity of the electric current of a circuit is 123A and the electric charge is 1.7C to find the time interval in which the electric charge is transported.

Given that,

Current, I = 123 A

Electric charge, q = 1.7 C

To find,

The time interval in which the charge is transported.

Solution,

The electric current is given by electric charge per unit time. So,

[tex]I=\dfrac{q}{t}\\\\t=\dfrac{q}{I}\\\\t=\dfrac{1.7}{123}\\\\t=0.0138\ s[/tex]

So, the required time is 0.0138 seconds.

Answer:

Concave lens spreads out light rays that are then refracted through it.: A concave mirror or a converging lens will only produce a virtual image at a point if the image is located beyond the focal point. By the focal point, we define the point that is more than one focal length away.

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°

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

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

Answer:

W= F × d

W= 2kn × 3.6

W= 7.2 J

Work is measured in Joules!

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 :)

Answer:

If you going to ask a question ask it accurately.

Explanation:

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.

Answer:

A. The expected electricity bill for this month is Rs 18,896.2

B. The item which consumed the most energy during the month is the electric cooker with a total consumption of 1,110Kw/Month

Explanation:

Step 1 - Identify electrical appliances

I only have 8 electrical appliances in my home.

Step 2 - Assign usage per hour and calculate wattage used /month

Step 3 - Add up all the Kw used per month and multiply by the cost of 1 Kw

Total Kilowatt Consumed/Month = 1110 +108+120+10+84.6+421.2+29.7+6.12

= 1,889.62Kw/Month

Total cost of energy consumed per month = 1889.62 * Rs 10

= Rs 18,896.2

Cheers!

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

Answer:

8.3m/s

Explanation:

Given parameters:

mass of clay ball  = 5kg

Speed of clay ball  = 25m/s

mass of clay ball at rest  = 10kg

speed of clay ball at rest  = 0m/s

Unknown:

Velocity after collision  = ?

Solution:

 Since the balls stick together, this is an inelastic collision:

   m1v1 + m2v2  = v(m1 + m2)

  5(25) + 10(0)  =  v (5 + 10)

         125 = 15v

           v  = 8.3m/s

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.

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.

Answer:

I’m. Nog sure

Explanation:

Answer:

For an object to accelerate, appropriate force must be applied to the object to cause it to change it’s velocity if it’s already in motion. However, to cause it to overcome static friction if it is at rest, and cause it to change it’s velocity

Explanation:

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)

Answer:

[tex]V_{B/A}=2i+2k[/tex]

Explanation:

The relative velocity can be calculated by means of the difference between vector B minus vector A.

[tex]V_{A}=i+2j-3k\\V_{B}=3i+2j-k\\V_{B}-V_{A}=(3-1)i + (2-2)j+(-1-(-3))k\\V_{B/A}=2i+2k[/tex]

Answer:

4048 = 115x/100.

Explanation:

Profit P = (15/100) X x.

P= 15x/100.

15x/100 = 4048- x.

4048 = 15x/100 + x.

4048 = 115x/100.

Answer:

Okay

Explanation:

First we should quickly remind ourselves of the equation for density:density= mass/ volumeTo calculate the density we need a method of measuring the mass of each object and another method for measuring the volume of each object. To measure the mass in both cases we can simply use a measuring balance. To measure the volume we will need to use 2 separate methods. For the cube we can simply measure the length, height and depth with a ruler, multiply our measurements and we obtain the volume. The statue is a little more tricky because it has an irregular shape so we can't use the ruler anymore. Instead we should use graduated tank/trough of water. First of all measure the amount of water in the tank before putting in the statue. Then submerge the statue in the water and take another measurement of the volume of water in the tank. The statue will displace the water in the tank giving a higher value. We finally subtract the initial volume from the final volume and we should obtain the volume of the statue.We now have all the measurements necessary to calculate the density of both objects!

Answer:

The oceanic plate will sink under

Explanation:

Due to erosion over time and the sudden shift, the continental plate will rise causing earthquakes, tsunami’s, etc..

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.