A weightlifter lifts a 500 N barbell with no acceleration, 1.25 meters. How much work did she do in lifting the weights?(step by step)

Answers

Answer 1

Answer:

–625 J

Explanation:

So, we got this formula for the work

W=mgd(Cosθ)

but remember when it's liftin somethin, its work gon be against the work of gravity, so

Cos180°= –1

W=500×1.25×(–1)

W= –625 J


Related Questions

How much current flows in the circuit if two resistors of 6 connected in parallel are
supplied with potential difference of 12 volts?​

Answers

Answer:

4 A

Explanation:

Firstly we need to calculate the equivalent resistance. Since, two resistors of 6 connected in parallel, so equivalent resistance will be given by,

[tex]\longrightarrow[/tex] 1/R = 1/R1 + 1/R2

[tex]\longrightarrow[/tex] 1/R = (1/6 + 1/6) Ω

[tex]\longrightarrow[/tex] 1/R = (1 + 1)/6 Ω

[tex]\longrightarrow[/tex] 1/R = 2/6 Ω

[tex]\longrightarrow[/tex] R = 6/2 Ω

[tex]\longrightarrow[/tex] R = 3 Ω

We know that,

[tex]\longrightarrow[/tex] V = IR

V denotes p.d (12V)I denotes currentR denotes resistance (3 Ω)

[tex]\longrightarrow[/tex] 12 = I × 3

[tex]\longrightarrow[/tex] 12 ÷ 3 = I

[tex]\longrightarrow[/tex] 4 Ampere = I

when you order clothes, does the sweater has to be longer than your shirt to fit you just like the shirt?

Answers

Answer:

Yes.⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

A 72 kg swimmer dives horizontally off a raft floating in a lake. The diver's speed immediately after leaving the raft is 3.8 m/s. If the time interval of the interaction between the diver and the raft is 0.25 s, what is the magnitude of the average horizontal force by diver on the raft?

Answers

Answer:

F = 1094.4 N

Explanation:

From impulse - momentum theorem, we now that ;

Impulse = momentum

Where;

Formula for impulse = force (F) × time(t)

Momentum = mass(m) × velocity(v)

Now, we are given;

Mass of swimmer; m = 72 kg

Speed; v = 3.8 m/s

Time; t = 0.25 s

Thus;

F × t = mv

F = mv/t

F = (72 × 3.8)/0.25

F = 1094.4 N

This value of force is the magnitude of the average horizontal force by diver on the raft.

A 5.0 kg block of ice is at rest at the top of a smooth inclined plane. The block is released and slides 2.0 m down the plane. Assuming there is no friction between the block and the surface, calculate
a) the gravitational potential energy at the top of the plane
b) the component of the weight parallel to the plane
c) the acceleration of the block
d) the velocity of the block at the bottom of the plane
e) the kinetic energy at the bottom of the plane. ​

Answers

Answer:

a) 98.1 Joules

b) 49.05 N × sin(θ)

c) 9.81 × sin(θ)

d) The velocity of the block at the bottom of the plane, v is approximately 6.264 m/s

e) 98.1 Joules

Explanation:

The given parameters of the block are;

The mass of the block, m = 5.0 kg

The distance down the plane the block slides, h = 2.0 m

The friction between the block and the surface = 0

Let θ represent the angle of inclination oof the plane

a) The gravitational potential energy, P.E. = m·g·h

Where;

g = The acceleration due to gravity ≈ 9.81 m/s²

∴ P.E. ≈ 5.0 kg × 9.81 m/s² × 2.0 m = 98.1 Joules

The gravitational potential energy, P.E. ≈ 98.1 Joules

b) The component of the weight of the block parallel to the plane, [tex]w_{\parallel}[/tex], is given as follows;

[tex]w_{\parallel}[/tex] = w × sin(θ) = m·g·sin(θ)

∴ [tex]w_{\parallel}[/tex] ≈ 5.0 kg × 9.81 m/s² × sin(θ) = 49.05 × sin(θ) N

The component of the weight of the block parallel to the plane, [tex]w_{\parallel}[/tex] ≈ 49.05 N × sin(θ)

c) The component of the weight along the inclined plane = The force with which the block moves along the inclined plane, therefore;

[tex]w_{\parallel}[/tex] = m·g·sin(θ) = m·a

Where a represents the acceleration of the block along the plane

Therefore, by comparison, we have;

g·sin(θ) = a

∴ a ≈ 9.81 × sin(θ)

d) Given that the motion of the block is 2.0 m downwards, we have;

The velocity of the block at the bottom of the plane, v² = 2·g·h

Therefore, v² ≈ 2 × 9.81 m/s²× 2.0 m = 39.24 m²/s²

v = √(39.24 m²/s²) ≈ 6.264 m/s

e) The kinetic energy at the bottom of the plane, K.E. = (1/2)·m·v²

∴ K.E. = (1/2) × 5.0 kg × 39.24 m²/s² = 98.1 J

A boy travels 12km east wards to a point B and then 5km southwards to another point C. Calculate the difference between the magnitude of the displacement of the boy and the distance travelled by him

Answers

The difference b/w the displacement and total distance traveled is 4km.

Explanation.

▪ total distance - displacement

= 17 km - 13 km

= 4 km...answer

You can see stars brighter than magnitude +6 with your naked eye under dark sky conditions, and you can also see the full moon at magnitude –13. (You can glance at the Sun, which is at magnitude –27, but you can't safely look at the Sun.) Given these limits, what is the dynamic range of the naked eye?

Answers

-6 uh 89 0 -+= 62 uwuwhhiwhiuhwiuhwuihhishishoknsk

¿ Sobre que superficie se desplazara mas rápidamente un tejo, sobre cemento o sobre cerámica? ¿por que?

Answers

Answer:

cemento potque es plano

An unstrained horizontal spring has a length of 0.40 m and a spring constant of 340 N/m. Two small charged objects are attached to this spring, one at each end. The charges on the objects have equal magnitudes. Because of these charges, the spring stretches by 0.033 m relative to its unstrained length. Determine (a) the possible algebraic signs and (b) the magnitude of the charges.

Answers

Answer:

(a) Both the charges are positive or negative.

(b) Teh value of each charge is 1.53 x 10^-5 C.

Explanation:

Spring constant, K = 340 N/m

Natural length, L = 0.4 m

stretch, y = 0.033 m

(a) Let the charge on each sphere is q and they repel each other so the nature of charge of either sphere may be both positive or both negative.  

(b) The electrostatic force is balanced by the spring force.

[tex]\frac{kq^2}{(L + y)^2}=Ky\\\\\\\frac{9\times 10^9 q^2}{(0.4 +0.033)^2} = 340\times0.033\\\\q= 1.53\times 10^{-5} C[/tex]

Imagine you see Mars rising in the east at 6:30 pm. Six hours later what direction would you face (look) to see Mars when it is highest in the sky

Answers

Answer:

The Mars appears in the direction of South.

Explanation:

Mars is rising in the east at 6: 30 PM. The period of rotation of earth is 24 hours.

So, 6 hours is the one fourth of the period of rotation of earth. Earth rotates counter clockwise on its axis, so after 6 hours, we see the Mars in the direction of South.

1. Use a micrometer to find the thickness of the foil you used. Do your data confirm the measured thickness? Determine the percentage difference between the measured thickness and the thickness you found in your experiment.

Answers

Answer:

Yes.

Explanation:

Yes, my data confirm the measured thickness because the micrometer measure precise thickness of any object. If the same instrument and right method is used for the measurement of the thickness of the foil then there is zero difference occur between the measured thickness and the thickness in your experiment so using right method can reduce or eliminate the difference between the measured thickness and the thickness in experiment.

_______ is an optical filter that passes light of a specific polarization and blocks waves of other polarizations.
a. Index of refraction
b. Laser
c. Polarizer

Answers

I’m not 100% sure but C. Would make sense

This filter picks out a specific polarization, so it makes a lot more sense to call it a polarizer than anything else.  (C)

This question is a lot like asking "What color is an orange ?".

The reservoir stores 6 500 000 m3 of water. The density of the water is 998 kg/m3. Calculate the mass of water in the reservoir. Give your answer in standard form.

Answers

Answer:

Mass = 64,870,000,000 kilograms

Explanation:

Given the following data;

Density = 998 kg/m³

Volume = 6,500,000 m³

To find the mass of water in the reservoir;

Density can be defined as mass all over the volume of an object.

Simply stated, density is mass per unit volume of an object.

Mathematically, density is given by the equation;

Density = mass/volume

Making mass the subject of formula, we have;

Mass = density * volume

Mass = 998 * 6,500,000

Mass = 64,870,000,000 kilograms

An airplane flies eastward and always accelerates at a constant rate. At one position along its path, it has a velocity of 32.7 m/s . It then flies a further distance of 48500 m , and afterwards, its velocity is 44.7 m/s . Find the airplane's acceleration.

Answers

Answer:

[tex]\quad[/tex]0.0095 m/s²

Explanation:

We have,

Initial velocity (u) = 32.7 m/sFinal velocity (v) = 44.7 m/sDistance travelled (s) = 48500 m

We are asked to calculate the airplane's acceleration.

By using the third equation of motion,

- = 2as

v denotes final velocityu denotes initial velocitya denotes accelerations denotes distance

➝ (44.7)² - (32.7)² = 2 × a × 48500

➝ 1998.09 - 1069.29 = 97000 × a

➝ 928.8 = 97000a

➝ 928.8 ÷ 97000 = a

0.0095 m/s² = a

A hot-air balloon is rising upward with a constant speed of 2.85 m/s. When the balloon is 2.50 m above the ground, the balloonist accidentally drops a compass over the side of the balloon. How much time elapses before the compass hits the ground

Answers

Answer:

Explanation:

You have to declare which way is plus -- up or down. I will use down.

vi = - 2.85       The balloon is going up. That is the minus direction.

a = 9.81

d =   2.50 meters  distance in this case is from the object to the ground.

d = vi*t + 1/2 a t^2

-2.50 = -2.85*t + 1/2 * 9.81 * t^2

-2.50 = -2.85*t + 4.905 * t^2           transfer the left to the right.

-4.905 t^2 + 2.85*t + 2.50 = 0

Use the quadratic formula to solve for t.

It turns out that t = 1.06

Una grúa eleva un tubo de concreto de
400 kg, con Movimiento rectilíneo uniforme,
con el
cable ABC. Determine la tensión que pueden
soportar los cables AB, BC y BD, sabiendo
que los cables AB=BC y la tensión que
soporta el cable AB es de 150 N.

Answers

Explanation:

Hydraulic Pressure-Control, On-Off Deluge Valve

FP-400Y-5DC

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E
How does the construction of dams positively affect natural resources?
by providing water for irrigation and restoring trees to areas where forests once existed
by creating reservoirs, preventing flooding, and renewing destroyed ecosystems
by preventing flooding, creating reservoirs, and providing water for irrigation
by renewing destroyed ecosystems and restoring trees to areas where forest once ersted

Answers

Answer:

by preventing flooding, creating reservoirs, and providing water for irrigation

Dams and waterways store and provide water for irrigation so farmers can use the water for growing crops. This idea goes way back into history. Irrigation is an important part of using water. In areas where water and rain are not abundant (like the desert), irrigation canals from rivers and dams are used to carry water.

Dams help in preventing floods. They catch extra water so that it doesn’t run wild downstream. Dam operators can let water out through the dam when needed.

Determine the amount of potential energy of a 4.2 kg book that is placed on a shelf with a height of 0.9 meters. Round your answer to one decimal place​

Answers

Answer:

that is a correct answer maybe .

Find the sum. Express the answer in scientific notation. (1.54 x 10^6)+(6.15 x 10^6)​

Answers

Answer:

[tex] { \tt{(1.54 \times {10}^{6}) + (6.15 \times {10}^{6}) }} \\ = { \tt{(1.54 + 6.15) \times {10}^{6} }} \\ = { \tt{7.69 \times {10}^{6} }}[/tex]

If an object is thrown in an upward direction from the top of a building 160 ft high at an initial speed of 30 mi/h, what is
its final speed when it hits the ground? (Disregard wind resistance. Do not reflect negative direction in your answer.)
ft/s
110 fus
100 ft/s
097 ft/s
91 ft/s
NEXT QUESTION
© ASK FOR HELP
TURN ITIN

Answers

Answer:

We can use  2 g H = v2^2 - v1^2    or

v2^2 = 2 g H + v1^2

Since 88 ft/sec = 60mph   we have 30 mph = 44 ft/sec

The object will return with the same speed that it had initially so the object

starts out with a downward speed of 44 ft/sec

Then v2^2 = 2 * 32 ft/sec^2 * 160 ft + 44 (ft/sec)^2

v2^2 = (2 * 32 * 160 + 44^2) ft^2 / sec^2 = 12180 ft^2/sec^2

v2 = 110 ft/sec

¿Cuántos electrones por segundo pasan a través de una sección de alambre que lleva una corriente de 0.70 A.?

Answers

Answer:

The number of electrons flowing per second is [tex]4.375\times 10^{18}[/tex].

Explanation:

How many electrons per second pass through a section of wire that carries a current of 0.70 A.?

Current, I = 0.7 A

time, t = 1 s

According to the definition of current, let the charge is q.

q = I t

q = 0.7 x 1 = 0.7 C

Let the number of electrons is n.

[tex]n =\frac{q}{e}\\\\n = \frac{0.7}{1.6\times 10^{-19}}\\\\n = 4.375\times 10^{18}[/tex]

6. An object is fired from the gound at 275 m/s at an angle of 55° N of E.
a. How far away did the object first hit the ground?
b. what is the maximum height that the object reaches? ​

Answers

there u go fella hope u understood

the bodies in this universe attract one another name the scientist who propounded this statement​

Answers

Answer:

It was proposed by Isaac Newton

Explanation:

The law of universal attraction of expression

          F = [tex]G \ \frac{m_1m_2}{ r^2}[/tex]G m1m2 / r ^ 2

where G is a constant, m₁ and m₂ are the masses of the bodies and r the distance between them.

It was proposed by Isaac Newton

With this law Newton explained that the force that pulls the moon towards the earth is the same as that which attracts an apple towards the earth

A wave travels at 330m/s^-1. the wavelength is found to be 2.4m.
Calculate the period of oscillation of a article in the medium transmitting the waves.
The frequency of oscillations of the source transmitting the wave

Answers

Answer: frequency 137.5

Time period 0.01sec

Explanation:

at which point is the Kinetic energy the lowest?​

Answers

Answer:

the lowest kinetic energy point is option D

(e) Find the height and orbital velocity of the geostationary satellite above the earth assuming earth as a sphere of radius 6370 km. [Radius of earth, R = 6370km, Acceleration due to gravity
= 10ms) ​

Answers

Answer:

I don't really know this one trust me am not lieing

Which of the following supports the theory of continental drift?
A. Mountains on different continents match up.
B. Earth's crust is all in one piece.
C. Earth has hot climates at the equator.
D. There is one continent on Earth.

Answers

Answer:

A. Mountains on different continents match up.

Explanation:

Due to the drifting/ moving apart of the continents, land masses is split therefore in case of a mountain that split, it matches the other part in another continent.

asset question.....only answers otherwise u will be reported ​

Answers

Answer:

C. 24 hrs

Explanation:

it takes the earth 24 hrs to make one full revolution.

Quickly pls!!! A wave with a wavelength of 0.5 m moves with a speed of 1.5 m/s. What is the frequency of the wave?
A. 2.0 Hz
B. 1.0 Hz
C. 0.33 Hz
D. 3.0 Hz

Answers

Speed/wavelength - 1.5m/s / 0.5 m
The frequency of the wave will be 3 or D.

ive an example of a pair of variables that have negative correlation. A. The quantity of fertilizers used and crop yield. B. The color of a​ person's shirt and the number of meals sold at Chinese restaurants. C. The number of physicists and the speed of sound. D. The number of winter coats sold and the temperature outside.

Answers

Answer:

D. The number of winter coats sold and the temperature outside.

Explanation:

A negative correlation can be described as a relationship existing between two variables such that as one of these variables goes up, the other variable would go down and vice versa.

With this explanation in mind, as the temperature outside increases, less winter coats would be sold because an increase in temperature would mean more heat and hotness. People would be uncomfortable wearing thick clothing.

This question is divided into two parts. This is part (a) of the question. A proton accelerates from rest in a uniform electric field of 580 N/C. At some later time, its speed is 1.00 x 106 m/s. (a) Find the magnitude of the acceleration of the proton. (Mass of the proton is 1.67 x 10-27 kg and charge is 1.60 x 10-19 C) (in the following options 10^10 m/s^2 is 1010 m/s2)

Answers

Answer:

The acceleration of proton is 5.56 x 10^10 m/s^2 .

Explanation:

initial velocity, u = 0

Electric field, E = 580 N/C

final speed, v = 10^6 m/s

(a) Let the acceleration is a.

According to the Newton's second law

F = m a = q E

where, q is the charge of proton and m is the mass.

[tex]a= \frac{q E}{m}\\\\a = \frac{1.6\times10^{-19}\times 580}{1.67\times 10^{-27}}\\\\a= 5.56\times 10^{10} m/s^2[/tex]

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