If a rock has a speed of 12 m/s as it hits the ground, from what height did it
fall, assuming its initial speed was zero? Its mass is 50 kg.
A. 600 m
B. 4.2 m
C. 12 m
D. 7.3 m

Answer:

0.4

Explanation:

A concave lens is a diverging lens, so it will always have a negative focal length. Image distance is always negative for a concave lens because it forms virtual images.

From the lens formula;

1/f = 1/u+ 1/v

- 1/2 = 1/3 - 1/v

1/v = 1/3 + 1/2

v= 6/5

v= 1.2 cm

Magnification = image distance/object distance

Magnification = 1.2cm/3cm

Magnification = 0.4

Answer: 2.43 s

Explanation:

Initial velocity is [tex]u=15.2\ m/s[/tex]

Final velocity [tex]v=23\ m/s[/tex]

Average acceleration is [tex]a_{avg}=3.2\ m/s[/tex]

Average acceleration is change in velocity in the given amount of time

[tex]\therefore a_{avg}=\dfrac{v-u}{t}\\\\\Rightarrow 3.2=\dfrac{23-15.2}{t}\\\\\Rightarrow t=\dfrac{7.8}{3.2}\\\\\Rightarrow t=2.43\ s[/tex]

Thus, 2.43 s is required to acquire that average acceleration with 23 m/s velocity .

Answer:

Average speed = 24 km/h

Explanation:

Given the following data;

Uniform speed A = 30 km/h

Uniform speed B = 20 km/h

To find the average speed;

Mathematically, the average speed of an object is given by the formula;

[tex] Average \; speed = \frac {total \; distance}{total \; time} [/tex] ..... equation 1

Total time = TA + TB

[tex] T_{A} = \frac {x}{30} [/tex]

[tex] T_{B} = \frac {x}{20} [/tex]

[tex] Total \; time = \frac {x}{30} + \frac {x}{20} [/tex]

[tex] Total \; time = \frac {5x}{60} [/tex]

Total distance = x + x

Total distance = 2x

Substituting the values into equation 1;

[tex] Average \; speed = \frac {2x}{\frac {5x}{60}} [/tex]

[tex] Average \; speed = \frac {2x*60}{5x} [/tex]

[tex] Average \; speed = \frac {120}{5} [/tex]

Average speed = 24 km/h

Answer:

a. Magnetic field is a location of a vector field around an electric current or magnet formed due to moving electric charges, or magnetic material and has a magnetic effect and exerts a force on other magnetic materials, electric current, and electric charges. The Earth's magnetic field that has the effect of turning a compass needle is an example of a magnetic field

b. The number of turns of the coil, N, in Diagram 1.1 > The number of turns of the coil, N, in Diagram 1.2

The pattern of the iron filings in Diagram 1.1 are closer with less space in between than the pattern of iron filings in Diagram 1.2

The angle of deflection of the ammeter pointer in Diagram 1.1 will be > The angle of deflection of the ammeter pointer in Diagram 1.2, given that the number of turns and current are inversely proportional

c. i. The pattern of the iron filings will have rings which are more closely arranged to each other as the strength of the magnetic field is increased

ii. As the number of turns is increased, the magnetic field is increased

Explanation:

Answer:

the force of resistance on the right team is 360 N

Explanation:

Given;

force of the left team, = 1000 N

total mass of the right team, m = 300 kg

acceleration of the right team, a = 1.2 m/s²

The force of resistance of the right team is calculated as;

Force = mass x acceleration

Force, F = 300 x 1.2

Force = 360 N

Therefore, the force of resistance on the right team is 360 N

Answer:

[tex] \rm 250000 \; cm^2 [/tex]

Explanation:

Refer to the attachment.

Answer:

F2 = 900 lbs

Explanation:

From pascal principle;

F1/A1 = F2/A2

Force on cylinder at left; F1 = 100 lbs

Diameter of cylinder at left; d1 = 2 inches

Diameter of cylinder at right; d2 = 6 inches

Formula for area of top of cylinder = πr²

Thus;

Area of top of left cylinder; A = π × 2² = 4π

Area of top of right cylinder; A = π × 6² = 36π

Thus;

100/4π = F2/36π

F2 = (36π × 100)/4π

F2 = 900 lbs

Answer:

[tex]T=7.5*10^{-5}[/tex]

Explanation:

From the question we are told that:

Radius [tex]r=2cm[/tex]

Work done [tex]W=1.5×10^-4 joules[/tex]

Generally the equation for Work done is mathematically given by

 [tex]W=T.dA[/tex]

Therefore

 [tex]T=\frac{W}{dr}[/tex]

 [tex]T=\frac{1.5*10^{-4}}{2}[/tex]

 [tex]T=7.5*10^{-5}[/tex]

Answer:

attached below

Explanation:

The initial conditions :

x(0) = - 9 inches = -3/4 ft

x'(0) = - 2 ft/sec

spring stretched  3 inches = 1/4 ft

mass = w / g = 4 Ib / 32 ft/sec^2 = 1/8  slug

the spring constant ( k ) = w / l  = 4 / ( 1/4 ) = 16 Ib/ft

applying the second law of motion

m d^2x/dt^2 +  b dx/dt  + kx

= 1/8 d^2x/dt^2  + 2 dx/dt  + 16 x

= d^2x/dt^2  + 16 dx/dt  +  128 x  ------- ( 1 )

we will resolve the above equation to obtain the required equation of motion  x( t )

Attached below is the remaining part of the solution

Solution :

When the spacecraft is at halfway point, the distance from the Earth as well as Mars are same. We have to account the masses of the planets. The gravitational force that is exerted by the Earth is greater because of its combined mass with the space probe.

The mass of Earth is greater than the mass of Mars. Therefore, the force of Earth is more than Mars.

Answer:200 Mpa

Explanation:

Given that diameter of cylinder = d = 1-25cm = 1.25 100 =0.0125m

Load or mass = m = Stress 0 = ? 2500kg

Solution: Formula N = F A

Area of Cross-section of cylinder = A=πr2 A = π(d/2) 2

= π(d2/4)

=(3.14)(0.0125)2/4

A = 1.226x10-4

F ・ mg = = F A 24500 2500 x 9.8 = 24500 N

1-226x10-4

1998 36 867.9

= 200 x 106 Pa

= 200 MPa

*Hope it helps you*

Good luck

Answer:

Explanation:

If the distance to the end of the road was 40 m, and she traveled back to where she started, she traveled a total distance of 80 m. It took her 100 seconds to travel the 80 m.

Based on the given distance-time graph, the number of seconds that Angela used to go to the end of the road and arrive back is 100 seconds.

The end of the road is 40m and coming back is also 40 m. The total distance is:

= 40 + 40

= 80m

The graph shows that to walk 80 meters, Angela took a 100 seconds because the line on the graph ends at 80 m and 100 seconds.

Find out more uses of distance-time graphs at https://brainly.com/question/13877898.

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The answer is C :), I think.

A scientific paper is the primary source. A primary source is an item, document, recording, or any other source. Option C is correct.

Scientific papers are a specific sort of written work with certain characteristics: they are often published in a periodical called a journal, whose sole objective is to publish this type of work.

A primary source is an item, document, recording, or any other source of information created during the period being studied in the academic area of history.

A scientific paper is the primary source.

Hence,option C is correct.

To learn more about the scientific paper, refer:

https://brainly.com/question/1716162

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[tex]option \: (a) \: is \: correct.[/tex]

Explanation:

Yes, I was wrong. Pressure increases as the area decreases.

As per the Figure A, the truck is so heavy and having a greater mass. So, the area of contact between the tyres and the road increases and decreases it's pressure on the road due to the increase in area.

As per the Figure B, You know the nature of Tomato that it is soft and smooth to touch and also lighter mass when it's compared with the truck. As it having a lighter mass, it can be cut through the sharp knife. The area of contact decreases and pressure increases on the vegetables.

Answer:

Option number B

Explanation:

The pressure is indirectly proportional to the area therefore pressure decreases when the area increases, and pressure increases when the area decreases

Answer:

1.25 m

Explanation:

From the question given above, the following data were obtained:

Force ratio = 2.5

Distance of load from the fulcrum = 0.5 m

Distance of effort =.?

The distance of the effort from the fulcrum can be obtained as illustrated below:

Force ratio = Distance of effort / Distance of load

2.5 = Distance of effort / 0.5

Cross multiply

Distance of effort = 2.5 × 0.5

Distance of effort = 1.25 m

Therefore, the distance of the effort from the fulcrum is 1.25 m

Answer:

PE = 3.92x10^16J

potential energy

Explanation:

PE = m*g*h

mass of water = 1000kg/m³

(4*10^10m³)*1000kg = 4*10^13kg

PE = (4*10^13kg)*(9.81m/s²)*(100m)

PE = 3.92x10^16J

Answer:

The law of momentum conservation can be stated as follows. For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision.

The amount of solar radiation received by Earth from the sun, known as insolation, is greatest when the sun is directly overhead a location.

The amount of solar radiation received by Earth from the sun is known as insolation, solar insolation is greatest when the sun is directly overhead a location.

The energy transferred from the Sun in the form of electromagnetic radiation is known as the solar energy

It can be used as thermal energy for various life purposes as well as for electricity conversion with the help of solar photovoltaic cells

The ratio of total electrical energy generated by a solar photovoltaic panel to its total thermal energy is known as solar energy efficiency. The solar panel's area and design have an impact on how energy-efficient it is.

Thus, the term "insolation" refers to the amount of solar radiation that Earth receives from the sun. Solar insolation is highest when the sun is directly overhead a location.

Learn more about solar energy from here, refer to the link;

brainly.com/question/9704099

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Answer:

the tension of the rope is 34.95 N

Explanation:

Given;

length of the rope, L = 3 m

mass of the rope, m = 0.105 kg

frequency of the wave, f = 40 Hz

wavelength of the wave, λ = 0.79 m

Let the tension of the rope = T

The speed of the wave is given as;

[tex]v = f\lambda = \sqrt{\frac{T}{\mu} } \\\\where;\\\\\mu \ is \ mass \ per \ unit \ length\\\\\mu = \frac{0.105}{3} = 0.035 \ kg/m\\\\v = f\lambda = 40 \times 0.79 = 31.6 \ m/s\\\\v = \sqrt{\frac{T}{\mu} } \\\\v^2 = \frac{T}{\mu} \\\\T = v^2 \mu\\\\T = (31.6^2)(0.035)\\\\T = 34.95 \ N[/tex]

Therefore, the tension of the rope is 34.95 N

Answer:

C. Increase in back emf

Explanation:

As the current through the field winding decreases the field strength also decreases and the back-emf is reduced, as a result the motor speeds up.

When the motor begins to speed-up, an additional back EMF is generated due to induction which reduces armature current. This also results in reduced strength of the field flux. The back emf generated is not enough to reduce the armature current which could stop the acceleration of the motor and the motor further accelerates.

Answer: hi your question is incomplete  attached below is the complete question

answer :

magnitude of acceleration :  | a | = g = 9.81 m/s^2

direction : a = - g j

Explanation:

Neglecting Air resistance

magnitude of acceleration :

| a | = g = 9.81 m/s^2

Direction of acceleration

a = - g j  ( given that the direction of acceleration is against the acceleration due to gravity i.e. in the opposite direction )

Answer:

Value of the resistors​ R = 2 ohm

Explanation:

Given:

Resistor R1 = 4 ohm

Resistor R2 = 4 ohm

Find:

Value of the resistors​ R

Computation:

We know that Resistor R1 and Resistor R2 connected in parallel series.

So,

Using common resistance in parallel series

⇒ 1/R = 1/R1 + 1/R2

⇒ 1/R = 1/4 + 1/4

⇒ 1/R = (1 + 1) / 4

⇒ 1/R = 2/4

⇒ R = 4/2

⇒ R = 2

Value of the resistors​ R = 2 ohm

Answer:

heuristic.

Explanation:

Psychology can be defined as the scientific study of both the consciousness and unconsciousness of the human mind such as feelings, emotions and thoughts, so as to understand how it functions and affect human behaviors in contextual terms.

This ultimately implies that, psychology focuses on studying behaviors and the mind that controls it.

A heuristic is an automatic mental shortcut or rule of thumb that avail people the opportunity to make quick and efficient judgement in decision-making process, as well as proffering solutions to a problem. Thus, it allows people to make decisions, pass probability judgement or proffer solutions to problem quickly and efficiently while applying minimal mental effort.

Basically, a heuristic helps an individual to shorten the decision-making time while paying less attention on thinking of his or her next course of action.

Hence, when you're advised to try working backward from the desired goal to the starting point or current state. This advice describes a heuristic.

Answer:

[tex]f = m \frac{v1 - v2}{t} \\ = 120 \times \frac{25 - 5}{2} \\ = 120 \times \frac{20}{2} \\ = 120 \times 10 \\ = 1200N \\ thank \: you[/tex]

Answer:

The correct option is a) 10 mph, 0 mph.

Explanation:

1. The average speed (S) is a magnitude given by:

[tex] S = \frac{D}{T} [/tex]  

Where:

D: is the total distance = 1 mi

T: is the total time = 6 min

[tex] S = \frac{D}{T} = \frac{1 mi}{6 min}*\frac{60 min}{1 h} = 10 mph [/tex]

Hence, the average speed is 10 mph.

2. The average velocity is a vector:

[tex] V = \frac{\Delta d}{\Delta t} = \frac{d_{f} - d_{i}}{t_{f} - t_{i}} [/tex]

Where:

[tex]d_{f}[/tex]: is the final distance                                    

[tex]d_{i}[/tex]: is the initial distance  

[tex]t_{f}[/tex]: is the final time                

[tex]t_{i}[/tex]: is the initial time

Since Juanita ran one mile around her school track, the final position is the same that the initial position, so the magnitude of the average velocity is zero.                                               

Therefore, the correct option is a) 10 mph, 0 mph.

I hope it helps you!          

Mass and volume are called physical quantities because they can be measured by using physical devices i.e. mass is measured by using beam balance and volume is measured by using metre scale .

Answer:

[tex]Q=50.3[/tex]

Explanation:

From the question we are told that:

Frequency [tex]F=330Hz[/tex]

Sound intensity drop [tex]I_d=2[/tex]

Time [tex]T=4s[/tex]

Therefore

Sound intensity Ratio

 [tex]\frac{I}{I_x}=\frac{1}{2}[/tex]

Generally the equation for Sound intensity is mathematically given by

 [tex]\frac{I}{I_x}=e^{-4\ \=t}[/tex]

 [tex]\frac{1}{2}=e^{-4\ \=t}[/tex]

 [tex]\=t =5.8s[/tex]

Generally the equation for Quality Factor is mathematically given by

 [tex]Q=2 \pi\frac{E}{\triangle E}[/tex]

 [tex]Q=2 \pi\frac{E}{\frac{E}{2*4}}[/tex]

 [tex]Q=50.3[/tex]