A weightlifter takes 0.5s to raise a barbell with 2 free-weights from the ground to a height of 0.9m. If each free-weight has a mass of 30kg and the barbell has a mass of 20kg, calculate how much power the weightlifter produces when lifting the barbell?​

Answers

Answer 1

Answer:

P = 1412.82 [Watt]

Explanation:

First we must calculate the total mass that makes up the barbell and the two free weights at each end of the barbell.

[tex]m=30+30+20\\m= 80 [kg][/tex]

Weight is now defined as the product of mass by gravitational acceleration.

[tex]w=m*g[/tex]

where:

m = mass = 80 [kg]

g = gravity acceleration = 9.81 [m/s²]

[tex]w=80*9.81\\w=784.8[N][/tex]

Now using the product of the weight by the distance traveled we can calculate the work.

[tex]W=w*d[/tex]

where:

W = work [J]

w = weight = 784.8 [N]

d = distance = 0.9 [m]

[tex]W=784.8*0.9\\W=706.41[J][/tex]

And power is defined as the relationship of work at a certain time. The potency is expressed by means of the following formula.

[tex]P=W/t\\P=706.41/0.5\\P=1412.82[W][/tex]


Related Questions

A 5-kg object is sliding to the right and encountering a friction force that slows it down. The coefficient of friction (μ) between the object and the surface is 0.1. What is the acceleration of the object? Note: There is no applied force here.

Answers

Answer:

The friction force is 4.9 N

[tex]a = 0.98\ m/s^2[/tex]

Explanation:

Friction Force

When an object is moving and encounters friction in the air or rough surfaces, it loses acceleration or speed because the friction force opposes motion.

The friction force when an object moves on a horizontal surface is calculated by:

[tex]Fr=\mu N[/tex]

Where [tex]\mu[/tex] is the coefficient of static or kinetics friction and N is the normal force.

If no forces other then the weight and the normal are acting upon the y-direction, then the weight and the normal are equal in magnitude:

N = W = m.g

Thus, the friction force is:

[tex]Fr=\mu W[/tex]

The object has a mass of m=5 Kg, calculate the weight:

W = 5 * 9.8 = 49 N

It encounters a friction force that slows it down. We are given the coefficient of friction μ = 0.1, thus the friction force is:

Fr=0.1 49 N = 4.9 N

The friction force is 4.9 N

Since the only force acting on the object is the friction force, thus the net force is F = 4.9 N, and the acceleration can be calculated by using the equation of Newton's second law:

F = m.a

Solving for a:

[tex]\displaystyle a = \frac{F}{m}[/tex]

[tex]\displaystyle a = \frac{4.9}{5}[/tex]

[tex]\mathbf{a = 0.98\ m/s^2}[/tex]

Question 6 of 15
6
The rate at which work is done is called power.
O A True
O B. False

I believe it’s true?

Answers

Answer: A) True, you are correct

==================================================

Explanation:

Power in physics is defined as

power = (change in work)/(change in time)

which shows that power is basically the rate of work done. We can think of it like a speed of sorts.

------------

For example, if you apply 100 joules of work over 2 seconds, then,

power = (100 joules)/(2 seconds)

power = (100/2) joules per second

power = 50 watts

A watt is defined to be a joule per second, and it's often used to measure how much electricity is consumed, but it has broader uses in physics as well.

a snowball thrown at an ice cream truck at Valley Forge in January sticks to the side. Into what form of energy was the mechanical energy changed

Answers

Answer:

Thermal Energy

Explanation:

I majored in Physics

When a snowball thrown at an ice cream truck at Valley Forge in January sticks to the side, the mechanical energy was  changed into thermal energy.

What is law of conservation of energy?

Energy cannot be created or destroyed, according to the rule of conservation of energy. However, it is capable of change from one form to another. An isolated system's total energy is constant regardless of the types of energy present.

The law of energy conservation is adhered to by all energy forms. The law of conservation of energy essentially says that all energy is conserved in closed systems, or systems that are isolated from their surroundings.

When a snowball thrown at an ice cream truck at Valley Forge in January, the mechanical energy was  changed into thermal energy and the edges of the ice melts and again due to temperature of the surrounding they freezes together and the snowball sticks to the side.

Learn more about energy here:

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why is physics to study the heat absorbed by the ocean​

Answers

Answer:

Heat is a source of energy

Explanation:

Just took the test

an object has an mass of 15 kg and is falling at a rate of 2.0 m/s what is the momentum?

Answers

Answer:

30 kg.m/s

Explanation:

The momentum of an object can be found by using the formula

momentum = mass × velocity

From the question we have

momentum = 15 × 2

We have the final answer as

30 kg.m/s

Hope this helps you

how much force would be needed to move a 100 kg object at the acceleration rate of 2 m/s

Answers

Answer: 200 N

Hope this helps! :)

If 200 ml of a gas at 27 degrees celsius is cooled to -33 degrees Celsius at a constant pressure , the volume will be
A 250ml
B 204ml
C 196ml
D 160ml

Answers

Given that,

Volume of gas, V₁ = 200 mL

Initial temperature, T₁ = 27°C

Final temperature, T₂ = -33°C

To find,

New volume of the gas.

Solution,

Initial temperature, T₁ = 27°C = 300 K

Final temperature, T₂ = -33°C = 240 K

Let V₂ is the new volume.

The relation between volume and temperature is given by :

[tex]\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}\\\\V_2=\dfrac{V_1T_2}{T_1}\\\\=\dfrac{200\times 240}{300}\\\\=160\ mL[/tex]

Hence, the volume will be 160 mL.

An 80.0kg person is standing on a scale in an elevator accelerating downward at 4.0m/s^2. What is the reading on the scale to the nearest newton?

Answers

Answer:

320 N

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 80 × 4

We have the final answer as

320 N

Hope this helps you

If it requires E joules of energy to raise a mass from the surface of the Earth to an altitude of 6,000 km above the Earth, how much energy is required to raise it from the surface to an altitude of 12,000 km?​

Answers

Answer:

To raise the mass to an altitude of 12,000 Km 2E joules are required.

Explanation:

Gravitational Potential Energy

It's the energy stored in an object because of its vertical position or height in a gravitational field.

It can be calculated with the equation:

U=m.g.h

Where:

m = mass of the object

h  = height with respect to a fixed reference

g  = acceleration of gravity, or [tex]9.8 m/s^2[/tex].

If a mass has a height h1, its potential energy is

[tex]U_1=m.g.h_1[/tex]

If a mass has a height h2, its potential energy is

[tex]U_2=m.g.h_2[/tex]

The ratio of both potential energies is:

[tex]\displaystyle \frac{U_2}{U_1}=\frac{m.g.h_2}{m.g.h_1}[/tex]

Simplifying:

[tex]\displaystyle \frac{U_2}{U_1}=\frac{h_2}{h_1}[/tex]

Solving for U2:

[tex]\displaystyle U_2=U_1.\frac{h_2}{h_1}[/tex]

Since U1=E:

[tex]\displaystyle U_2=E.\frac{12,000~Km}{6,000~Km}[/tex]

[tex]U_2 = 2E[/tex]

To raise the mass to an altitude of 12,000 Km 2E joules are required.

An object that falls and accelerates solely as a result of gravity is said to be in
(2 points)
A. terminal velocity
B. free fall
C. air resistance
D. terminal acceleration

Answers

I think the answer is c

a beaker weighs 0.4N when empty and1.4N when filled with water what does ot weigh when filled with brine of density 1.2 g/cm3

Answers

Answer: 1.6 N

Explanation:

The weight of an object is calculated as:

W = g*m

where:

g = gravitational acceleration = 9.8m/s^2

m = mass of the object.

We also know that:

mass = density*volume.

or:

m = d*v

Let's start:

The weight of the beaker is 0.4N

And the weight of the beaker filled with water is 1.4N

Then the weight of the water alone will be:

1.4N - 0.4N = 1N = (d*v)*9.8m/s^2

And we know that the density of the water is:

1 g/cm^3

But we are working with Newtons, then we need to rewrite this with kilograms as the mass unit, we can use that:

1000g = 1kg

Now we can rewrite the density as:

d = 1 g/cm^3 = 1*(1/1000) kg/cm^3 = 0.001 kg/cm^3

Replacing that in the above equation, we get:

With this, we can find the volume that the water occupies.

W = 1 N = v* 0.001 kg/cm^3*9.8m/s^2

       1 N /( 0.001 kg/cm^3*9.8m/s^2 ) = 102.04 cm^3.

Now, when we fill it with a brine with a density of 1.2 g/cm^3, the mass of this brine in a volume of  102.04 cm^3 be:

M = (1.2 g/cm^3)*( 102.04 cm^3) = 122.448 g

Rewriting this in kg we get:

M = 122.448 g = (122.448/1000) kg = 0.122448 kg

Then the weight of this brine is:

M = 0.122448 kg*9.8m/s^2 = 1.2 N

And the beaker weighs 0.4N, then the beaker filled with this brine will weight:

1.2 N + 0.4N = 1.6 N

which number is larger value : 5.6*10^23 or 8.9*10^6

Need Help

Answers

Answer:

5.6*10^23. if 10^n is greater, that means its the larger value. hope dis helps

Explanation:

A student releases a marble from the top of a ramp and the marble increases speed steadily and travels 190 cm in 4.10 s what's the marbles final speed

Answers

Answer:

The value is  [tex]v = 92.68 \ cm/s[/tex]

Explanation:

From the question we are told that

     The distance traveled is [tex]d = 190 \ cm = 1.9 \ m[/tex]

     The  time taken is  [tex]t = 4.10 \ s[/tex]

Generally from kinematic equation we have that

      [tex]s = ut + \frac{1}{2} at^2[/tex]

Here u is the initial velocity of the marble and the value is [tex]u = 0 \ m/s[/tex]

So

      [tex]1.90 = 0* t + \frac{1}{2} a (4.10 )^2[/tex]

=>   [tex]1.90 = 0* t + \frac{1}{2} a (4.10 )^2[/tex]

=>    [tex]a = 0.226 \ m/s^2[/tex]

Generally from kinematic equations we have that

     [tex]v = u + at[/tex]

=>   [tex]v = 0 +0.226 * 4.10[/tex]

=>   [tex]v =0.9268 \ m/s[/tex]

Converting to  cm/s

=>    [tex]v =0.9268 * 100[/tex]

=>    [tex]v = 92.68 \ cm/s[/tex]

The magnitude of vector vector A is 84.9 m and it points in the +y axis direction. The magnitude of vector vector B is 195.0 m and it points at an angle of 41.0° counterclockwise from +x axis. The magnitude of vector vector C is 126.2 m and it points in the +x axis direction.

Answers

Solution:

The magnitude of A vector is 84.9 m in the positive y-axis direction.

So the X component of A =0

     the Y component of A = 84.9 m

Now the magnitude of B vector is 195 m and it makes an angle of 41° in the direction from the positive x-axis direction.

So  the X component of B = B cos 41°

                                           = 195 x cos 41°

                                           = 195 x 0.75   = 146.25 m

   the Y component of B = B sin 41°

                                           = 195 x sin 41°

                                           = 195 x 0.65   = 126.75 m

Now it is given that vector C has a magnitude of 126.2 m and it makes a direction towards the positive x-axis.

So the X component of C =126.2 m

     the Y component of C = 0

Comparing all these, we get

1. B vector has the largest X component

2. B vector has the largest Y component

A skier skids to a stop at the bottom of a mountain.
What is the equal and opposite force for the force of the skier's friction pushing on the mountain as
described by Newton's third law?

Answers

Answer:

Friction of the mountain on the skier in the opposite direction

Explanation:

answered it on khan academy

Friction of the mountain on the skier in the opposite direction.

What is Newton's  third law?

A force is a push or a pull that acts upon an object as a results of its interaction with another object. Forces result from interactions.

Forces result from contact interactions (normal, frictional, tensional, and applied forces are examples of contact forces) and other forces are the result of action-at-a-distance interactions (gravitational, electrical, and magnetic forces).

There are two forces resulting from this interaction - a force on the chair and a force on your body. These two forces are called action and reaction forces and are the subject of Newton's third law of motion.

Therefore, Friction of the mountain on the skier in the opposite direction.

To learn more about Friction, refer to the link:

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can you answer the b. thanks

Answers

Answer:

current going into a junction in a circuit is EQUAL TO the current comming out of the junction.

Explanation:

Krichhoff's Current Law

Kirchhoff's current law (1st Law) states that current flowing into a node (or a junction) must be equal to current flowing out of it.

What disease did Isaac Newton barely escape?

Answers

Answer:

the great plague

Explanation:

An electrically charged atom is called an

Answers

Answer:

It's called an ion. Excuse me if I'm wrong.

Explanation:

Electrically charged atoms are called ions

Explication- positive ions are called cations and negative ions are called anions. Atoms have two types of charged particles protons have a positive charge and are found in nucleus Electrons have a negative charge and are found outside the nucleus.

Hope this helps

A crate is being pulled down an incline as shown in the figure. With respect to the crate's direction of motion, which of the following forces does only negative work on the crate?

Answers

Answer:Fn

Explanation:

There is an accident up the road from your car. You see other cars ahead of you. Who will stop first?

A fully-loaded big rig truck

An empty truck

A midsized van

A small car

Answers

Answer:

According to the 2010 U.S. Census, there are approximately 8 million people living in Virginia. This is 2.8 million less than 4 times the population of Nevada.

What is the population of Nevada?

The first step is to  on both sides.

The second step is to  on both sides.

The population of Nevada is  million.

Explanation:

a small car!! hope this helps

4. Bob creates his personal profile collage by drawing his favorite things. This is his ___________.

A. artistic self
B. social self
C. professional self
D. private self

Answers

Artistic self because it says by drawing his favorite things hope this helps
A. Kdkdjdhshshdhdhdhd

A student attaches a block to a force sensor and pulls it across a frictionless table. The sensor measures the block's acceleration What type of mass does the student measure ?
a. gravitational mass
b. inertial mass
c. neither

Answers

Answer:Inertial mass

Explanation:When we measure gravitational mass we find the strength of an object's interaction with a gravitational field.

When we measure inertial mass we find an object's resistance to being accelerated by a force.

An object's gravitational mass and inertial mass are the same.

We apply a force and measure the resulting acceleration, so we can use Newton’s second law to find the inertial mass.

how many teeth shows signs of decay?​

Answers

Answer:

what do you mean

Explanation:

a force of 50 newtons pulls a rope attached to a 150 newton sled across a horizontal surface at a constant velocity of 5 meters per second. The rope is at an angle of 35 degrees above the horizontal. calculate the magnitude of the frictional force acting on the sled? Show all work, including the equation and substitution with units.

Answers

Answer:

I don't know the answer I hope you find it tho good luck##

where is the centre of mass of a system of two particles is situated?​

Answers

Answer:

In a two particle system, the center of mass lies on the center of the line joining the two particles.

A train going 14m/s moves 250 m while accelerating to a stop. What is the train’s deceleration?

Answers

Answer:

-0.056 is the deceleration

Explain why different types of musical instruments sound different, even though they play the same notes.

Answers

each musical instrument is build differently which allows it to portray a different sound kinda like humans with their voices

Help i will do anything for this. its a serious grade

Answers

Answer: 10 has more potential energy because its longer

1 has less potential energy because its shorter

Explanation:

Potential energy directly depends on height of body as

[tex]\\ \sf\longmapsto P.E=mgh[/tex]

[tex]\\ \sf\longmapsto P\propto h[/tex]

Higher the height higher the potential energy

Object at height 10m has more potential energy.

3) A school bus traveling at 12 m/s has a momentum of 144,000 kg.m/s.
What is the mass of the bus?

Answers

Answer:

does this have picture so I can solve

The mass is 12,000

144,000 divided by 12 = 12,000

Momentum = mass × velocity

Brainliest would be appreciated. :)

Can u anser 5,6 on the picture

Answers

Answer: Number 6 is Periods

Explanation:

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