Find the work done by a weightlifter lifting a 20kg barbell 2.2 m upward at a constant speed.

Explanation:

v=u+at, where v,u,a and t are the final velocity, initial velocity, acceleration and time, respectively.

For t=0 s to t=30 s , a =8 m/s 2.

For t=30 s to t=50 s , a = 5 m/s 2.

For t=50 s to t=110 s , a = 0 m/s 2.

For t=110 s to t=130 s , a is such that the body comes to rest at the end of this period.

For t=0 s to t=30 s ,v=0+8t⇒v=8t m/s.

At t=30s,v=8×30=240 m/s.

For t=30 s to t=50 s ,v=240+5(t−30)⇒v=90+5t m/s

At t=50s,v=90+5×50=340 m/s.

For t=50 s to t=110 s ,v=340 m/s.

For t=110 s to t=130 s ,v=340+a(t−110).

The body comes to a halt at t=130 s ⇒0=340+a(130−110).

0=340+20a⇒a=−34020=−17 m/s2.

For t=110 s to t=130 s ,v=340−17(t−110)=2210−17t m/s.

Answer:

Force = 9600N

Explanation:

If this is the right question, there should have been a question before about the what the change in the momentum of the ball was. The answer to that was 9.6kg m/s. For this part, we divide this by the time taken which was 0.001s which give us the resultant force.

resultant force = change in momentum ÷ time

= 9.6kgm/s ÷ 0.001s

= 9600N

The maximum and minimum variation between the true and magnetic poles is 180 degrees and 0 degrees respectively.

The poles of the earth are the North and South poles.

The North is taken as the reference point.

The true north is a fixed point on the globe and gives the true North and South poles.

The Magnetic north is the direction that a compass needle points to as it aligns with the Earth's magnetic field and gives the magnetic North and South poles.

The maximum maximum and minimum variation between the true and magnetic poles is 180 degrees and 0 degrees respectively.

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26.676 × 10³ kg is the weight of the aluminum rod.

Given:

Length of cylindrical rod (h) = 45 cm

Diameter of a cylindrical rod = 4.53 cm

Radius of a cylindrical rod (r) = 2.3 cm

The density = 3.7*10^3kg/m^3

Volume of a cylindrical rod = πr²h

                                             = 3.14× (2.3)² × 45

                                             = 747.89 cm

                                             = 7.4789 m

To find weight ;

                         ρ = [tex]\frac{Mass}{Volume}[/tex]                  ; ρ = Density

                        Mass = ρ × Volume

                                  = 3.7 × 7.48 × 10³

                                  =27.676 × 10³ kg

Therefore, the weight of the aluminum rod is 27.676 × 10³ kg.

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Answer:

To check whether a chemical equation is balanced or not we usually look if elements on the product side are numerically equal to the reactant side or not.

A. Na + MgCl₂ → NaCl + Mg

Reactant Product

Na = 1 1

Mg = 1 1

Cl = 2 1

Unbalanced

B. 2LiOH + H₂S → Li₂S + 2H₂O

Reactant Product

Li = 2 2

S = 1 1

O = 2 2

H = 4 4

Balanced

C. AgNO₃ + NaCl → NaNO₃ + AgCl

Reactant Product

Ag = 1 1

N = 1 1

Na = 1 1

Cl = 1 1

O = 3 3

Balanced

D. 3PBr₃ + 2Cl₂ → 3PCl₃ + 2Br₂

Reactant Product

P = 3 3

Br = 9 4

Cl = 4 9

Unbalanced

Therefore, equations B and C are balanced chemical equations.

a protostar will continue to collapse due to gravity until it reaches the main sequence, and then gravitational collapse will stop when fusion of hydrogen begins.

A protostar serves as a very young star which is very small in mass and still developing its mass from parent molecular cloud.

However, it can be affected by gravity because , when there is not  collapse on the gravity, if there is fusion of hydrogen begins in it.

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Answer:

3 767 400 joules

Explanation:

4.186 J/g-C   is the specific heat of water

25  to 115  is 90 degrees C change

10 000 g   is 10 kg of water

10 000 * 90 * 4.186 = 3 767 400 Joules

Answer:

[tex]\huge\boxed{\sf \lambda = 2 m}[/tex]

Explanation:

Frequency = f = 200 Hz

Velocity = v = 400 m/s

Wavelength = λ = ?

v = fλ

Put the givens in the formula

400 = (200)λ

Divide 200 to both sides

400/200 = λ

2 m = λ

λ = 2 m

[tex]\rule[225]{225}{2}[/tex]

Answer:

Newton's second law states that force is directly proportional to the product of mass and acceleration.

so if you hit a baseball with a bat it will accelerate according to the applied force.

A driver have to stop for a school bus when the red lights are flashing and there is no barrier between his/her vehicle and the bus.

Traffic rules are rules that are expected to follow by the road users for the safety of everyone using the road.

For instance, when the red lights are flashing , it simply means to stop, while the green light means that the vehicle can continue to move, and yellow light means to be at alert to move.

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Answer:

energy only

Explanation:

Water waves transfer energy via oscillations of the water molecules, but the the water molecules themselves do not move along the wave.

This is why when the boy jumps into the water, his kinetic energy is transferred by the water molecules across the pool, but neither the boy nor the water particles move along with the wave.

The speed of the car moving after 7 seconds will be 31.5 m/sec.

The change of distance with respect to time is defined as speed. Speed is a scalar quantity. It is a time-based component. Its unit is m/sec.

The given data in the problem is

m is the mass of the car = 1289  Kg.

u is the initial velocity  = 0 m/sec

a is the acceleration in m/sec²

v is the velocity after 7 seconds =?

The power developed is;

P =FV

F=ma

P=maV

183831=1289 kg × a × V

a = 142.61 / V

From Newton's second equation of motion;

V=u+at

V=0+at

V=(142.61/V)t

V²=142.61 × 7

V=31.5 m/sec

Hence, the speed of the car moving after 7 seconds will be 31.5 m/sec.

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The formula for the energy in a capacitor , u in terms of q and c is q²/2c

The energy of a capacitor u = 1/2qv where

Also, the capacitance of a capacitor c = q/v where

So, v = q/c

Substituting v into u, we have

u = 1/2qv

= 1/2q(q/c)

= q²/2c

So, the formula for the energy in a capacitor , u in terms of q and c is q²/2c

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The time of motion of the track star is determined as 0.837 s.

The time of motion of the track star is calculated as follows;

T = (2u sinθ)/g

where;

T = (2 x 12 x sin20)/9.8

T = 0.837 s

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Explanation:

first change m/s to km/hr and time 1 year to hour b/c we are asked the to give in km. so,

v=17,000 m/s = 17000×3600/1000 = 61,200 km/hr

t= 1 year= 365 days =365day×24 hr/day = 8,760hr

therefore, V = s/t from this s = v×t =61200×8760 =536,112,000 Km

Answer:

V initial = 29.4 m.s²

Explanation:

( Using the laws of motion)

V final = V initial + Acceleration × time

0 = V initial + ( -9.8)(3)

29.4 = V initial

* I took upward as positive that's why I substituted -9.8 *

* for V final we know that at maximum height the ball is not moving thats why is = 0 *

The speed of Vc at the instant bead collide is 1.38 m/s and the instant speed of Vd at the instant bead collide is 0.106 m/s.

The force of attraction on the beads are due to both gravitational force and electrostatic force

As gravitational force is very weak force as compared to electrostatic force the net force will be due to electrostatic force only.

Net Force = Electrostatic force

Net Force = K q1 q2 / r²

Net Force = (9 × 10⁹) (2.5 × 10⁻⁹) (1 × 10⁻⁹) / (14 × 10⁻³) (as distance between there centre of mass is 14 mm)

Net Force = (9 × 2.5 × 10⁻⁶) / 14

Net Force = 1.6 × 10⁻⁶

For bead c

Force = Mc × Ac = 1.6 × 10⁻⁶

(1 × 10⁻³) × Ac = 1.6 × 10⁻⁶

Ac = 1.6 × 10⁻³

Acceleration of bead C is 1.6 × 10⁻³ m/s²

For bead d

Force = Md × Ad = 1.6 × 10⁻⁶

(1.7 × 10⁻³) × Ad = 1.6 × 10⁻⁶

Ad = 0.94 × 10⁻³

Acceleration of bead D is 0.94 × 10⁻³ m/s²

Let us suppose bead C travels y distance before collision

So bead D should travel 12-y distance before collision

So speed of both the beads before the collision can be find out by using newton third law of motion

For bead C

Vc² - Uc² = 2 Ac s

Vc² = 2 × 1.6 × 10⁻³ × y

Vc² = 3.2 × 10⁻³ × y

Vc = √(3.2 × 10⁻³ × y)

For bead D

Vd² - Ud² = 2 Ad s

Vd² = 2 × 0.94 × 10⁻³ × (12-y)

Vd² = 1.88 × 10⁻³ × (12-y)

Vd = √(1.88 × 10⁻³ × (12-y))

Applying energy conservation

initial = final

0 + 0 = (1/2)McVc² - (1/2)MdVd²

(1/2)McVc² = (1/2)MdVd²

McVc² = MdVd²

1 × 10⁻³ × 3.2 × 10⁻³ × y = 1.7 × 10⁻³ × 1.88 × 10⁻³ × (12-y)

3.2 × y = 3.2 × (12-y)

y = 12-y

2y = 12

y = 6

Putting the value of y in Vc and Vd

Vc = √(3.2 × 10⁻³ × y)

Vc = √(3.2 × 10⁻³ × 6)

Vc = √(19.2 × 10⁻³)

Vc = √0.0192

Vc = 1.38 m/s   (approximately)

Vd = √(1.88 × 10⁻³ × (12-y))

Vd = √(1.88 × 10⁻³ × (12-6))

Vd = √(1.88 × 10⁻³ × 6)

Vd = √(11.28 × 10⁻³)

Vd = √0.01128

Vd = 0.106 m/s   (approximately)

So the speed of Vc at the instant beads collide will be approximately 1.38 m/s and Vd at the instant speed the beads collide will be approximately 0.106 m/s.

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Explanation:

Hello, nice to meet you.

this answer will help for you

The initial horizontal velocity of the rock, in m/s is 21.241 m/s.

When an object is thrown at an angle from the horizontal direction, the object is said to be in projectile motion. The object which follows the projectile motion.

Time taken by the stone to reach the ground is

t = √2h/g

t = √(2x 86)/9.81

t = 4.19s

The horizontal velocity is

V(x)  = Horizontal distance traveled / Time taken t

Put the values, we get

V(x) = 89 m/4.19 s

V(x) = 21.241 m/s

Thus, the horizontal velocity is 21.241 m/s

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Answer = B

Explanation:

Sustainability is the most appropriate as it means meeting our own needs without compromising the ability of future generations to meet their own needs.

She can use the information of redshift of a celestial body is to find the age and distance of the object.

'Red shift' is a critical idea for astronomers. The frequency of the light is increased, so the light is observed as moving towards the red side of the range.

Tabitha knows the redshift value of a particular celestial object. She uses this information to observe the consequence of the redshift.

Thus, the red shift value is used to determine the age and distance of the object.

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Answer:

A (the age and distance of the object)

Explanation:

Answer:

19.55 m/s

Explanation:

Here is HOW to get the answer:

Speed = wavelength * freq

           = 1.7 * 11.5 = 19.55 m / s

Explanation: A) half wave rectifier

B) Full wave rectifier :

1) central tapped

2) bridge rectifier

i hope this was helpful to you

The generated statements that set the properties of the labels, buttons, and forms end up automatically within the InitializeComponent() method.

The InitializeComponent method in programming is the that have code that works with codes that  creates and initializes the creates and initializes the user interface objects .

Conclusively, when a statement is generated, to  when set the properties of the labels , it will definitely been felt in the InitializeComponent() method automatically.

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The local group of galaxies which the Milky Way belong to is the Virgo Supercluster. C

The Virgo Supercluster as known as the Local Supercluster is a mass concentration of galaxies that contains the Virgo Cluster and Local Group which in turn contains the Milky Way and Andromeda galaxies, as a host as others galaxies.

Therefore, the local group of galaxies which the Milky Way belong to is the Virgo Supercluster.

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Answer:

[tex]\boxed {Density = 4800 kg/m^{3}}[/tex]

Explanation:

Formula :

[tex]\boxed {Density = \frac{Mass (kg)}{Volume (m^{3})}}[/tex]

Convert volume into standard unit :

⇒ 250000 cm³ × 10⁻⁶

⇒ 0.25 × 10⁶ × 10⁻⁶

⇒ 0.25 m³

Solve for density :

⇒ Density = 1200 kg / 0.25 m³

⇒ Density = 1200 × 4 kg/m³

⇒ Density = 4800 kg/m³