Pablo's engineering team has developed a new material that is strong enough to withstand major impacts, including bullets, without breaking or deforming. He plans to design a new type of motorcycle helmet using the material as its outside covering. A prototype of the helmet is shown below. Pablo knows that other types of motorcycle helmets have outside coverings that bend and deform slightly on impact. So if Pablo's new helmet is going to be as effective at protecting people's heads as existing helmets, he'll need to

A.
slightly reduce the total mass of the new helmet by reducing the amount of internal cushioning.
B.
maximize the total mass of the helmet by adding flexible steel to the outside covering.
C.
increase the amount of cushioning on the inside of the new helmet to help it absorb impacts.
D.
use a thicker outside covering than other helmets to help prevent deformation even further.

Answer:

A

Explanation:

1000ml = 1l

397ml = 0.397l

Given that,

Mass of a woman, m = 60 kg

She runs up a staircase 15 m high in 20 s.

To find,

Power expanded.

Solution,

Power = rate of doing work

[tex]P=\dfrac{W}{t}\\\\P=\dfrac{mgh}{t}\\\\P=\dfrac{60\times 9.8\times 15}{20}\\\\=441\ W[/tex]

So, the required power is 441 W.

Answer:

The final speed of the semi truck is 30.11 m/s.

Explanation:

Given;

mass of the motorcycle, m₁ = 200 kg

initial speed of the motorcycle, u₁ = 40 m/s

mass of the semi truck , m₂ = 18,000 kg

initial speed of the semi truck, u₂ = 30 m/s (same direction as u₁)

If the two vehicles stick together after collision, the final speed of the motorcycle will be equal to final speed of the semi truck = v

Apply the principle of conservation of linear momentum;

m₁u₁ + m₂u₂ = v(m₁ + m₂)

(200 x 40) + (18,000 x 30) = v(200 + 18,000)

8000 + 540,000 = v(18,200)

548,000 = v(18,200)

[tex]v = \frac{548,000}{18,200} \\\\v = 30.11 \ m/s[/tex]

Therefore, the final speed of the semi truck is 30.11 m/s.

Answer:

[tex]\frac{dI}{dt} =-3.04*10^-^4amps/sec[/tex]

Explanation:

From the question we are told that

Voltage change [tex]\frac{dv}{dt}=-0.03volts/sec[/tex]

Resistance change [tex]\frac{dR}{dt}=0.02ohms/sec[/tex]

Resistance [tex]R=100[/tex]

Current [tex]I=0.02[/tex]

Generally the equation for ohms law is mathematically represented as

[tex]V=IR[/tex]

Therefore

[tex]\frac{dv}{dt} =R\frac{dI}{dt} +I\frac{dR}{dt}[/tex]

[tex]\frac{dv}{dt} =R\frac{dI}{dt} +I\frac{dR}{dt}[/tex]

Resolving the Rate of current changing [tex]\frac{dI}{dt}[/tex] as subject of formula

[tex]\frac{dv}{dt} =R\frac{dI}{dt} +I\frac{dR}{dt}[/tex]

[tex]R\frac{dI}{dt} =\frac{dv}{dt} -I\frac{dR}{dt}[/tex]

[tex]\frac{dI}{dt} =\frac{1}{R} (\frac{dv}{dt} -I\frac{dR}{dt})[/tex]

Therefore

[tex]\frac{dI}{dt} =\frac{(-0.03) -(0.02)(0.02)}{100}[/tex]

[tex]\frac{dI}{dt} =-3.04*10^-^4amps/sec[/tex]

Therefore the current decreases at a rate

[tex]\frac{dI}{dt} =3.04*10^-^4amps/sec[/tex]

Answer:

Natural Sciences

Explanation:

This network would fall under the lens of Natural Sciences. This is based on what the family is currently watching. Nature documentaries focus on our Planet as well as all the wildlife in it. In these documentaries, they talk about how and why certain things in nature occur. All of this would be considered educational information on the subjects of Earth Science and Biology which are main subcategories under the lens of Natural Sciences.

Answer:

depends... do you add suger to your ketchup?

Explanation:

Answer:

As the string vibrates, it "moves" the particles in the air, generating what we know as a soundwave.

Because this soundwave is generated by the wave-like motion of the string, makes sense that the soundwave will have some characteristics in common with the standing wave on the guitar string. This means that both waves will have the same normal modes. (So if the principal mode of the vibrating string has a frequency of 440hz, to soundwave also will have that main frequency, and we will hear an A). You can hear almost all the normal modes when you pluck a guitar string, particularly in music, these are called "overtones" or "harmonics"

Answer: 11.53 %

Explanation:

Given

area [tex]A=10\ m^2[/tex]

Voltage V=50 V

current I=15 A

Array running at [tex]650\ W/m^2[/tex]

Power  [tex]P=VI=50\times 15=750\ W[/tex]

Efficiency [tex]\eta=\frac{750}{650\times 10}\times 100=11.53\%[/tex]

Given that,

Charge, q₁ = 7.03 nC

Charge, q₂ = 4.26 nC

Distance, r = 1.75 m

To find,

The magnitude of the electrostatic force that one charge exerts on the other.

Solution,

The force between two charges at a distance is given by the formula as formula :

[tex]F=\dfrac{kq_1q_2}{r^2}\\\\F=\dfrac{9\times 10^9\times 7.03\times 10^{-9}\times 4.26\times 10^{-9}}{(1.75)^2}\\\\=8.8\times 10^{-8}\ N[/tex]

So, the required force is [tex]8.8\times 10^{-8}\ N[/tex].

The question is incomplete. The complete question is :

If the entire population of Earth were transferred to the Moon, how far would the center of mass of the Earth-Moon population system move? Assume the population is 7 billion, the average human has a mass of 65 kg, and that the population is evenly distributed over both the Earth and the Moon. The mass of the Earth is 5.97×1024 kg and that of the Moon is 7.34×1022 kg. The radius of the Moon’s orbit is about 3.84×105 m.

Solution :

Given :

Mass of earth, [tex]$M_e = 5.97 \times 10^{24} \ kg$[/tex]

Mass of moon, [tex]$M_m = 7.34 \times 10^{22} \ kg$[/tex]

Mass of each human, [tex]$m_p =65 \ kg$[/tex]

Therefore mass of total population, [tex]$M_p = 65 \times 7 \times 10^{9} \ kg$[/tex]

                                                           [tex]$M_p = 4.55 \times 10^{11} \ kg$[/tex]

Let the earth is at the origin of the coordinate system. Then,

Since [tex]$M_e>> M_p$[/tex]

         [tex]$M_m>> M_p$[/tex]

Hence if we shift all the population on the moon there will be negligible change in the mass of the moon and earth. Hence there will not be any significant shift on the centre of mass. i.e.

      [tex]$X_{cm} = \frac{5.97 \times 10^{24}+ 7.34 \times 10^{22} \times 3.84 \times 10^5}{5.97 \times 10^{24}+ 7.34 \times 10^{22}}$[/tex]

              [tex]$= 4.68 \times 10^6 \ m$[/tex]

[tex]$ 4.68 \times 10^3 \ km$[/tex] from the earth.

Answer:

0.33s

Explanation:

hope this is the correct ans

Answer:

24.775N

Explanation:

According to Newton's second law

\sum Fx = ma

F- Ff = ma

F and Ff are the forces acting on the object

m is the mass

a is the acceleration

Given

Ff = 10N

m = 7.5kg

a = 1.97m/s²

Required

F

Substitute the given parameters into the formula

F - 10 = 7.5(1.97)

F-10= 14.775

F= 10+14.775

F = 24.775N

Hence the greatest possible magnitude of the other force is 24.775N

Answer:

    v₁ = -0.8087 m / s

Explanation:

To solve this problem we can use the conservation of momentum, for this we define a system formed by the man, the skateboard and the brick, therefore the force during the separation is internal and the momentum is conserved

Initial instant. When they are united

        p₀ = 0

Final moment. After throwing the brick

        [tex]p_{f}[/tex] = (m_man + m_skate) v1 + m_brick v2

the moment is preserved

        p₀ = p_{f}

        0 = (m_man + m_skate) v₁ + m_brick v₂

        v₁ = -  [tex]\frac{ m_{brick} }{m_{man} + m_{skate} } v_{2}[/tex]

the negative sign indicates that the two speeds are in the opposite direction

let's calculate

        v₁ = - [tex]\frac{2.5}{67 + 4.10} 23.0[/tex]

        v₁ = -0.8087 m / s

Given :

A rope 6m long is fixed at one end, the other end is attached to a light string so that it is free to move.

The speed of waves on the rope is 18 m/s.

To Find :

The frequency of the second harmonic.

Solution :

We know, for second harmonic wave :

Wavelength = Length of rope

[tex]\lambda = L\\\\\lambda = 6 \ m[/tex]

Now, we know frequency is given by :

[tex]Frequency = \dfrac{Speed}{Wavelenght}\\\\f = \dfrac{18 \ m/s}{6\ m}\\\\f = 3 \ s^{-1}[/tex]

Therefore, the frequency of the second harmonic is 3 s⁻¹.

Answer:

Explanation:

The ray of light that hits the polished surface is called the incident ray. The ray that gets reflected away is called the reflected ray. The point at which the light hits the surface is called the point of incidence. If a line is drawn perpendicular to that point, it is called the normal.

Answer:

3.6, make sure you study

Answer:

l think the correct answer is 1.GAA GUC

Answer:

it is due to anamolous expansion of water as water cools from 4dg.c to 0dg.c. it expand making ice lighter than water to float

Answer:

distance = speed × time

Explanation:

the unit of distance is meter(m)

but the formula differs according to the given

Answer:

585lb

Explanation:

Given the following

F1 = 235lb

F2 = 350lb

The resultant is expressed as;

FR = F1+F2

Substitute the given values

FR = 235+350

FR = 585lb

Hence the magnitude of the resultant is 585lb

Answer:

F = force

f = friction

u = coefficient of friction

R = normal reaction force

a = Acceleration

m = mass of block

g = gravity

f = uR

F = Ma

Say the block is moving to the right.

The 146N force thus acts to the right, and the friction force to the left, since it resists movement.  

The 146N force acts to the right, but the horizontal component of it is 146 cos 50  = 93.84: So this is the force to the right.

Since F = uR and we're trying to find u, we need both F and R. R is easy to get since it is just m x g. This is in fact already given as the weight 350N. So R = 350.

The block is moving at a constant speed, so the force to the right must = the force to the left.

F = ma, so 93.84 - f = (350/g) x 0

This means f must be 93.84 also.  

so  we have f = uR,  

      93.84 = u x 350

so u = 0.268 or  

0.27 to 2dp.  

Hope you understand this.

Explanation:

The coefficient of friction is 0.26 if the 46N force is needed to pull a 350 N block across a horizontal surface at a constant speed by a rope making an angle of 50 degrees with the floor.

It is a type of opposition force acting on the surface of the body that tries to oppose the motion of the body. its unit is Newton (N). Mathematically it is defined as the product of the coefficient of friction and normal reaction.

We know:

f = uR

Where f is the friction force and u is the coefficient of friction, R is the normal reaction force.

The horizontal component of 146N is:

F' = 146cos50°

F' = 93.84 N

Since F  = mass×acceleration

Because the block is traveling at a constant speed, the right-hand force must equal the left-hand force.

F' = f = 93.84 N

93.84 = u x 350   (R = 350N)

u = 0.26

Thus, the coefficient of friction is 0.26 if the 46N force is needed to pull a 350 N block across a horizontal surface at a constant speed by a rope making an angle of 50 degrees with the floor.

Learn more about the friction force here:

https://brainly.com/question/1714663

#SPJ2

Explanation:

The water molecules begins to leave their fixed position and begins to move as the temperature increases.

When ice melts, it undergoes a state change from solid to liquid and with increasing temperature becomes a gas.

Answer:

The mass of Jupiter is 1.9 x 1027 kg. It is hard to fully understand a number that large, so here are a few comparisons to help. It would take 318 times Earth's mass to equal Jupiter's.

Explanation:

Answer:

it's c. or A. not b.

Explanation:

.................

Answer:

10.46m/s

Explanation:

Given

Distance = 5.58m

Required

magnitude of the velocity'

Using the equation of motion expressed as

v² = u² + 2gS

v² = 0  +2(9.8)(5.58)

v² = 109.368

v= √109.368

v = 10.46m/s

Hence the magnitude of the velocity of the of the chain is 10.46m/s

Answer:

Iodine is element number 53. Iodine has 53 protons and 53 electrons (because it has no charge the number of protons equals the number of electrons). Iodine-131 has 131 protons and neutrons.

Explanation:

Answer:

1 m

Explanation: