1. The first stage of stellar formation is the assembly (or formation) of a_______ . 2. Stars form in clouds. 3. When a cloud collapses it into smaller and smaller pieces till those pieces reach stellar masses. 4. As the density increases, the fragments become_______ , which________ the temperature of the cloud and inhibits further fragmentation. 5. The _______then condense into rotating globs of gas that serve as stellar embryos. 6. During this stage the surface temperature_______ and luminosity_________ despite decreasing size. 7. The central temperature and pressure increase as the potential energy is converted to energy due to contraction.

Answer:

The hypothesis may or may not be true and needs to be tested. It might be the answer to the problem. Hence, it must be tested thoroughly. When these predictions are tested again and again in independent scientific experiments and gets verified, the hypothesis is converted into a scientific theory.

Answer:

Explanation:

The velocity ratio of  a wheel and axle is the ratio of the radius (R) of the wheel to the radius (r) of the axle. It is expressed as;

VR = R/r

Since radius = diameter/2

VR = (D/2)/(d/2)

VR = D/d

D is the diameter of the wheel and 'd' is the diameter of the axle.

Given VR = 3 and d = 5cm

3 = D/5

D = 15 cm

If the diameter of the wheel is 15cm, the radius of the wheel will be 15/2 = 7.5cm.

b) Workdone by the load = Load * distance moved by load

Given load = 60kg

Distance moved by load = 2π*radius of axle

Distance moved by load  = 2π(0.025) = 0.157

workdone by load = 60* 0.157 = 9.42J

Effort = Workdone by load/distance moved by the wheel

Effort = 9.42/2π(0.075)

Effort = 9.42/0.471

Effort = 20kg

Hence the effort applied is 20kg

c) MA = Load/Effort

MA = 60/20

MA = 3

d) Efficiency = MA/VR * 100%

Efficiency = 3/3 * 100%

Efficiency = 100%

Answer:

PFA

:-)

Explanation:

Derived Quantities

Answer:

These are quantities calculated from two or more measurements

Explanation:

They can't me measured directly.

They can only be computed.

They are calculated in PHYSICAL SCIENCE.

hope it helps.

Answer:1m

Explanation:

2n=0.4m

5n=?

5n×0.4/2n=1m

Answer:

perpendicular to

Explanation:

it means perpendicular to .....should u come across something like this / / , this one means parallel to .....

Answer:

perpendicular

Explanation:

Some of the most popular symbols are:

Heart symbol: this represents love, compassion and health.

Dove symbol: this represents peace, love, and calm.

Raven symbol: this represents death and doom.

Tree symbol: this represents growth, nature, stability, and eternal life.

Owl symbol: this represents wisdom and intelligence.

Answer:

c

Explanation:

The marginal cost curve image  has been attached from which we can clearly, indicate that

ATC = average total cost

AFC = average fixed cost

AVC = average variable cost.

From the graph we can indicate that the marginal cost curve

(c) Lies above the AVC curve when the AVC curve slopes downward.

Answer: A. 2.7 x 10^2 joules

Explanation: I’m sorry for the guy above me!

Answer:

“They may feel colder but that's only an illusion,” Dr. Begley says. “Copper mugs actually absorb heat from the room faster than a glass.” Copper is an excellent thermal conductor, meaning it transfers heat from hot sources (like the room or your hand) to cold sources (like your drink) very efficiently.

Explanation:

Answer:

Because there is no net force acting o an object in equilibrium.

Explanation:

When object is in equilibrium (either at rest or moving with constant velocity, the net force acting o it is zero.A vector can only have zero magnitude fall of its components are zero this means that all forces acting on the object are balanced.

Explanation:

To find the average of these numbers, we just have to add the three numbers together and divide by 3.

Answer:

50m/s.

Explanation:

Let's take acceleration as A and speed as S:

A = 5m/s²

S = A × 10s = 5 × 10 = 50m/s

The answer is 50m/s.

Answer:

50m/s

Explanation:

Given:

a=5m/s^2

t=10s

Required:

v=?

Formula:

a=v/t

Solution:

a=v/t

v=a*t

v=5m/s^2*10s

v=50m/s

Hope this helps ;)❤❤❤

Answer:

1800m

Explanation:

rearrange speed= distance/time

to distance=time*speed

1.2*1500=1800

Sarai's displacement in meters will be 1800 when it strolls to the right with an average speed of 1.2m/s for 1500 seconds.

Speed is defined as the ratio of the distance moved by the object at a particular time. The unit of speed is measured in the meter per second, miles per hour, etc.

Average velocity is defined as the sum of all the distances traveled by an object to the time taken by the object to cover the total distance.

Given that Sarai strolls to the right with an average speed of 1.2m/s for 1500 seconds.

To calculate the distance traveled by the object convert the velocity formula into the form of the distance formula then solve for the value of distance.

Velocity = Distance / time

1.2 = Distance / 1500

Distance = 1.2 x 1500= 1800 meters

Therefore, Sarai's displacement in meters will be 1800 when it strolls to the right with an average speed of 1.2m/s for 1500 seconds.

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Answer:

B.

Explanation:

as there is a '-' sign before the magnification value, it forms a real image.

so the last two options get cancelled.

as the value of magnification is 0.87 ie. lesser than 1, we can say that the image is smaller.

The type of image is formed by a lens if m = -0.87 would be smaller than the object and the object is real

A lens is a transmissive optical tool that employs refraction to focus or disperse a light beam. The power of the lens is expressed in the dioptre which is the reciprocal of the focal length of the lens.

The image formation through the lens is calculated with the help of the lens formula given as follows

1/f = 1/v - 1/u

where f is the focal length of the lens

u is the distance of the object from the lens

v is the distance of the image formed from the

magnification (m) = size of image /size of the object

As given in the problem image is formed by a lens if m = -0.87

Thus, the negative sign represents that the image formed by the object is real, and the magnitude of the magnification is less than 1 this represents that size of the image is smaller than the size of the object.

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Answer:

Explanation:

Energy of gamma ray = 2.2233 MeV

Let mass of neutron be n  amu  

mass defect of deuteron = 2.013553212 - ( 1.007 276 467 + n ) u .

in terms of energy this mass defect will be equal to energy of gamma ray

1 amu = 931 MeV

931 [ 2.013553212 - ( 1.007 276 467 + n ) ] =  2.2233

( 1.007 276 467 + n ) -  2.013553212  = .00238807733

n = 1.008664822 amu

so mass of neutron = 1.008664822 amu

Answer:

80 N.

Explanation:

The following data were obtained from the question:

Mass (m) = 20 Kg

Initial velocity (u) = 5 m/s

Final velocity (v) = 17 m/s

Time (t) = 3 secs

Force (F) =.?

Next, we shall determine the acceleration of the body.

Acceleration is simply defined as the rate of change of velocity with time. Mathematically, it is expressed as:

Acceleration = change of velocity /time

Acceleration (a) = (final velocity (v) – initial velocity (u)) / time (t)

a = (v – u) /t

With the above formula, we can obtain the acceleration of the body as follow:

Initial velocity (u) = 5 m/s

Final velocity (v) = 17 m/s

Time (t) = 3 secs

Acceleration (a) =?

a = (v – u) /t

a = (17 – 5) /3

a = 12/3

a = 4 m/s²

Finally, we shall determine the force applied to the body as follow:

Force (F) = mass (m) x acceleration (a)

F = ma

Mass (m) = 20 Kg

Acceleration (a) = 4 m/s²

Force (F) =.?

F = ma

F = 20 x 4

F = 80 M.

Therefore, the force applied on the body is 80 N.

Answer; 4.4cm

Explanation: There is a ruler upon which the cylinder start from 1.4cm and reaches 10.2cm

distance traveled =10.2-1.4=8.8

since this cylinder is small so the linear distance can be approximately taked as rotational distance(as in case of point charge) so

2x2πxr =8.8

so the circumference will be 2πr=4.4cm

Explanation:

The answer is option B

The number of reactant molecules and product molecules is even.

Answer:

0.25 m/s

Explanation:

Average velocity = change in displacement / change in time

v = (1.5 m − 2.5 m) / (6 s − 2 s)

v = -0.25 m/s

The average speed is 0.25 m/s.

Answer:

0.25 m/s

Explanation:

khan academy

Answer:

2660 m

Explanation:

Sum of the forces in the first 6.00 s:

∑F = ma

F − mg = ma

35.0 N − (0.800 kg) (10 m/s²) = (0.800 kg) a

a = 33.75 m/s²

The height it reaches during this time is:

Δy = v₀ t + ½ at²

Δy = (0 m/s) (6.00 s) + ½ (33.75 m/s²) (6.00 s)²

Δy = 607.5 m

The velocity it reaches is:

v = at + v₀

v = (33.75 m/s²) (6.00 s) + 0 m/s

v = 202.5 m/s

After the battery runs out, the drone is in free fall.  At the highest point, the velocity is 0.  The height at this point is:

v² = v₀² + 2aΔy

(0 m/s)² = (202.5 m/s)² + 2 (-10 m/s²) (h − 607.5)

h ≈ 2660 m

Answer:

12 i. The work done by Wale = 107.910 kJ

The work done by Lekan = 117.720 kJ

Total work done = 225.36 kJ

ii. Wale's power =  4.3164 kW

Lekan's power = 3.924 kW

Wale has more power and is more powerful than Lekan

13. 313.92 N

Explanation:

i. The work done, W = Force, F × Distance moved by the force, D

The given parameters are

The mass of Wale = 55 kg

The mass of Lekan = 60 kg

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

The motion force of Wale and Lekan are;

Motion force of Wale = 9.81 × 55 = 539.55 N

Motion force of Lekan = 9.81 × 60 = 588.6 N

The work done by Wale = 539.55 × 200 = 107910 J = 107.910 kJ

The work done by Lekan= 588.6 × 200 = 117720 J = 117.720 kJ

107910 + 117720 =225630 J = 225.36 kJ

ii. Power = Work done/time

Wale finished the race in 25 s, therefore, his power = 107910/25 = 4316.4 W

Lekan finished the race in 30 s, therefore, his power = 117720/30 = 3924 W

Wale has more power and is more powerful than Lekan

13. The velocity ratio = 5

V. R. = Distance moved by effort/(Distance moved by load)

Efficiency = 80%

Work done by effort = x

Work done by machine = Efficiency × Work done by effort  = 0.8 × x

Distance moved by effort, E = V. R. × Distance moved by load, D = 5 × D

Work done by effort = Force × Distance moved = 200×9.81× E

Work done by effort = 1962×E = 1962×E = 1962×5×D

Work done by machine = 1962 × D, when D = 1, we have;

0.8 × 1962×1 = 1569.6 J

Work done by effort = Force × Distance moved

Work done by effort = Force × 5×D = Force × 5 (D = 1)

From the principle of conservation of energy, we have;

Energy is neither created nor destroyed

Therefore

Work done by effort = Force × 5 = 1569.6 J

Force = 1569.6 /5 = 313.92 N.

Answer:

OPTION (C)

Explanation:

m(magnification) = -0.4 means a real, inverted and diminished image is formed in front of the mirror.

Answer:

Since water has a higher specific heat than copper.

Explanation:

Dimensionally speaking, the specific heat of a material ([tex]c[/tex]) is represented by:

[tex][c] = \frac{[Energy]}{[Mass]\cdot [Temperature]}[/tex]

The specific heats of water and copper are [tex]4186\,\frac{J}{kg\cdot ^{\circ}C}[/tex] and [tex]390\,\frac{J}{kg\cdot ^{\circ}C}[/tex], respectively. Let suppose that temperature change and masses of water and copper are the same. Then, a kilogram of water takes a longer time than a kilogram of copper since the first has a higher specific heat.

Answer:

5.3333 sec

Explanation:

initial speed: u = 108km/hr or 30 m/s

final speed: v = 0m/s

distance travelled: s = 80m

time the car took to stop: = t sec

[tex]v^{2} - u^{2}[/tex] = 2as,

a = ([tex]v^{2} - u^{2}[/tex])/2s

a = (0-900)/160

a = -5.625 [tex]ms^{-2}[/tex]

v = u + at,

t = (v - u)/a

t= (0 - 30)/(-5.625)

t = 5.3333 sec

Answer:

The distance the car travels is 115500 m in S.I units

Explanation:

Distance d = vt where v = speed of the car and t = time taken to travel

Now v = 99 km/h. We now convert it to S.I units. So

v = 99 km/h = 99 × 1000 m/(1 × 3600 s)

v = 99000 m/3600 s

v = 27.5 m/s

The speed of the car is 27.5 m/s in S.I units

We now convert the time t = 70 minutes to seconds by multiplying it by 60.

So, t = 70 min = 70 × 60 s = 4200 s

The time taken to travel is 4200 s in S.I units

Now the distance, d = vt

d = 27.5 m/s × 4200 s

d = 115500 m

So, the distance the car travels is 115500 m in S.I units

Answer:

b. varies inversely with the square of the distance from the center of Earth.

Explanation:

Comparing the Newton's law of universal gravitation and second law of motion;

from Newton's second law of motion,

F = ma ............. 1

from New ton's law of universal gravitation,

F = [tex]\frac{GMm}{r^{2} }[/tex] ........... 2

Equating 1 and 2, we have;

mg =  [tex]\frac{GMm}{r^{2} }[/tex]

g = [tex]\frac{GM}{r^{2} }[/tex]

Therefore, the acceleration due to gravity near Earth, g, is inversely proportional to the square of the distance from the center of Earth.

this process is called parellelogram method of resolving vectors.

Explanation:

It is given that,

The Displacement x of particle moving in one dimension under the action of constant force is related to the time by equation as:

[tex]x=4t^3+3t^2-5t+2[/tex]

Where,

x is in meters and t is in sec

We know that,

Velocity,

[tex]v=\dfrac{dx}{dt}\\\\v=\dfrac{d(4t^3+3t^2-5t+2)}{dt}\\\\v=12t^2+6t-5[/tex]

(a) i. t = 2 s

[tex]v=12(2)^2+6(2)-5=55\ m/s[/tex]

At t = 4 s

[tex]v=12(4)^2+6(4)-5=211\ m/s[/tex]

(b) Acceleration,

[tex]a=\dfrac{dv}{dt}\\\\a=\dfrac{d(12t^2+6t-5)}{dt}\\\\a=24t+6[/tex]

Pu t = 3 s in above equation

So,

[tex]a=24(3)+6\\\\a=78\ m/s^2[/tex]

Hence, (a) (i) v = 55 m/s (ii) v = 211 m/s and (b) 78 m/s²

Answer:

The correct option is;

3. The total mechanical energy is constant as the block moves back and forth

Explanation:

The total mechanical energy is the sum of the potential and kinetic energies of the system

For a system that is isolated from the effects of external forces, but being acted upon by the internal conservative forces within the system, the total mechanical energy is constant

For a black and spring system, we have total mechanical energy, E = 1/2×K×A².

Where;

K = Constant

A = The amplitude of motion

Therefore, where there is no loss to friction, with A, remaining constant, the total mechanical energy will be constant.

Answer:

The expected time is 2.28 hours.

Explanation:

The speed of storm = 35 km/hr

The distance between the house and the storm = 80 km.

Now, we have to find the time taken by storm to arrive at the house. Here, we can determine the time by dividing the distance with speed.

The time, taken by storm =  Distance/speed

The time, taken by storm = 80 / 35

The time, taken by storm = 2.28 hours.