I need help pls now ​plleeeeeeeeaaassseeeee

Answer:

Explanation:

Given parameters

initial velocity u = 4.9m/s

height of drop H = 100m

acceleration due to gravity g = -9.8m/s²(since the body is ascending i.e moving against gravity)

Required

time taken by the packet to reach the ground 't'

Using the equation of motion

S = ut+1/2gt²

0-100 = 4.9t+1/2(-9.8)t²

-100 = 4.9t-1/2(9.8)t²

-100 = 4.9t-4.9t²

4.9t-4.9t² +100 = 0

4.9t²-4.9t² -100 = 0

Multiplying through by 10

49t²-49t-1000 = 0

Using the general equation t = (-b±√b²-4ac)/2a

t = -(-49)±√(-49)²-4(49)(-1000)/2(49)

t = 49±√(2401+196000)/2(49)

t = 49±√(198401)/98

t = 49±√(198401)/98

t = 49±449.42/98

t = (49+449.42)/98

t = 494.42/98

t = 5.04secs

Hence, it took the packet 5.04secs to reach the ground

The final velocity is calculated using the formula v = u + at

v = u-gt

v = 4.9-(9.8)(5.04)

v = 4.9-49.392

v = -44.492m/s

This shows that the final velocity is 44.49m/s(moving downwards)

Answer:

Explanation:

Take note that when the fuel of the rocket is consumed, the acceleration would be zero. However, at this phase the rocket would still be moving up until all the forces of gravity would dominate and change the direction of the rocket. Hence, there will be a need to calculate two distances, one from the ground until the point where the fuel is consumed and from that point to the point where the gravity would change the direction.

Given:

a = 76.8 m/s^2

t = 1.99 s

Solution:

d = vi (t) + 0.5 (a) (t^2)

d = (0) (1.99) + 0.5 (76.8) (1.99)^2

d = 0+38.4×3.9601

d = 152.068m

vf = vi + at

vf = 0 + 76.8 (1.99)

vf = 152.83 m/s (velocity when the fuel is consumed completely)

Then, we calculate the time it takes until it reaches the maximum height.

vf = vi + at

0 = 152.83+(-9.8) (t)

0 = 152.83 + (-9.8) (t)

-152.83 = -9.8t

t = 152.83/9.8 s

t = 15.59s

Then, the second distance

d= vi (t) + 0.5 (a) (t^2)

d = 152.83 (15.59) + 0.5 (-9.8) (15.59^2)

d = 2382.6197- 1190.93

d = 1191.68m

Then, we determine the maximum altitude:

d1 + d2 = 152.068 m + 1191.68m = 1343.748m

Explanation:

5 km en 15 min.

= 5000 metros en 900 segundos

dividimos

la velocidad es de 5,56m/s

Espero que te sirva

Answer:

The color blue emerges at 19.16° and the color red emerges at 19.32°.

Explanation:

The angle at which the two colors emerge can be calculated using the Snell's Law:

[tex]n_{1}sin(\theta_{1}) = n_{2}sin(\theta_{2})[/tex]

Where:

n₁ is the refractive index of the incident medium (air) = 1.0003

n₂ is the refractive index of the refractive medium:

    blue light in crown glass = 1.524

    red light in crown glass = 1.512

θ₁ is the angle of the incident light = 30°

θ₂ is the angle of the refracted light                            

For the red wavelengths we have:

[tex] \theta_{2} = arcsin(\frac{n_{1}sin(\theta_{1})}{n_{2}}) = arcsin(\frac{1.0003*sin(30)}{1.512}) = 19.32 ^{\circ} [/tex]

For the blue wavelengths we have:

[tex] \theta_{2} = arcsin(\frac{n_{1}sin(\theta_{1})}{n_{2}}) = arcsin(\frac{1.0003*sin(30)}{1.524}) = 19.16 ^{\circ} [/tex]

Therefore, the color blue emerges at 19.16° and the color red emerges at 19.32°.  

I hope it helps you!

Answer:

114m

Explanation:

s=ut + 1/2 at^2

s=23 m/s ×3s + 1/2×3×3s^2×10m/s^2

= (69+45)m

= 114m

Answer:

H = 0.06 kWh

Explanation:

Given that,

Power of an electric lamp, P = 60 W

Voltage, V = 240 V

It is operated for 1 hour

We need to find the heat generated by the lamp. Heat generated is given by :

[tex]H=P\times t\\\\H=60\ W\times 1\ h\\\\H=60\ Wh\\\\H=0.06\ kWh[/tex]

So, 0.06 kWh of the heat is generated by the lamp.

Answer:

the lens is located in the eye. by changing its shape, the lens changes the focal distance of the eye. in other words,it focuses the light rays that pass through it (and onto the retina) in order to create clear images of objects that are positioned

at various distances.

Answer:

a) increases

Explanation:

Almost all substance or material undergoes expansion due to heating. Heat gives thermal energy to the molecules of a substance increasing their body temperature. The temperature of a substance is the measure of the average kinetic energy of the molecules of that substance. When the temperature of a substance increases, the molecules begin to agitate and try to move far from each other, leading to either a linear, area, or cubic expansion, or all three of them. Metals like copper expand very well on heating, and their expansion is relatively minute, but very observable. When the face of such a copper is scratched to give and angle, heating the copper uniformly will cause the copper to expand, leading to an increase in the angle formed.

Answer:

[tex]\boxed{0}[/tex]

Explanation:

Momentum is the measure of mass in motion.

[tex]\sf momentum = mass \times velocity[/tex]

An object at rest has a velocity of 0.

[tex]p=mv[/tex]

[tex]p = 25 \times 0[/tex]

[tex]p=0[/tex]

The momentum of an object at rest is always 0.

Answer:

3.24×10⁸ J, or 324 MJ

Explanation:

"kWh" is a kilowatt-hour.  It's the energy used by 1 kilowatt of power after one hour.

A kilowatt is a kilojoule per second.

90 kWh

= 90 kW × 1 hr

= 90 kJ/s × 1 hr

= 90 kJ/s × 3600 s

= 324,000 kJ

= 324,000,000 J

The energy is 3.24×10⁸ J, or 324 megajoules.

Explanation:

a) The displacement is the area under the curve.

Δx = ½ (10 s) (20 m/s) + (20 s) (20 m/s) + ½ (10 s) (20 m/s)

Δx = 600 m

b) The car is accelerating when the velocity is changing.  This happens between t = 0 and t = 10, and between t = 30 and t = 40.

c) Average speed = displacement / time

v_avg = 600 m / 40 s

v_avg = 15 m/s

Explanation:

The ratio of the areas is the square of the ratio of the radii.

A/A = 3.16² = 9.99

The ratio of the volumes is the cube of the ratio of the radii.

V/V = 3.16³ = 31.6

Answer:

The volume of the cavity is 0.013m^3

Explanation:

To find the volume of the cavity, the major parameter missing is the diameter of the cavity itself. we can obtain this using the following steps:

Step one:

Obtain the volume of the cylinder by dividing the mass of the cylinder by the density.

Volume of the cylinder = 2.1 / 11.053 =0.19[tex]m^{3}[/tex]

Step two:

From the volume of the cylinder, we can get the radius of the cylinder.

[tex]radius = \sqrt{\frac{V}{\pi \times h}} = \sqrt{\frac{0.19}{\pi \times 0.32}} =0.44m[/tex]

Step three:

From the cross-sectional area, we can obtain the radius of the cavity.

Let the radius of the cavity be = r, while the radius of the cylinder be = R

CSA of cavity =

[tex]\pi({R^2}-r^2) = CSA\\0.65 = \pi (0.32^2-r^2)\\r= 0.115m[/tex]

Step Four:

calculate the volume of the cavity using volume =[tex]\pi r^2 \times h[/tex]

Recall that the cavity has the same height as the original cylinder

[tex]volume = \pi \times 0.115^2\times 0.32= 0.013m^3[/tex]

Answer:

Well if they playing a game like that

Answer:

option b

Explanation:

the heavier one will have twice the kinetic energy of the lighter one

The heavier one will have twice the kinetic energy of the lighter one. Hence, option (B) is correct.

Given data:

The mass of object 1 is, m.

The mass of object 2 is, 2m.

Here, the concept of kinetic energy is used. The kinetic energy of an object is the energy possessed by the object by virtue of its motion. Motion means something related with the speed.

And the mathematical expression for the kinetic energy is given as,

[tex]KE =\dfrac{1}{2}mv^{2}[/tex]

Here,

m is the mass of body.

v is the speed of body.

Now considering the kinetic energy for the two given objects as,

[tex]KE=\dfrac{1}{2}mv^{2}\\\\KE'=\dfrac{1}{2}(2m)v^{2}[/tex]

Comparing both the values of kinetic energies, we find that,

KE' = 2KE

Thus, we can conclude that the heavier one will have twice the kinetic energy of the lighter one. Hence, option (B) is correct.

Learn more about the kinetic energy here:

https://brainly.com/question/12669551

Answer:

a) 4 m

b) 24 m/s

c) 0.174 kg

Explanation:

a) Tension in string equation

The information given are;

The wavelength is equal to the rope length , λ = L

The tension = 100 N

The displacement of a point on the rope is y(x, t) = (0.1 m) sinπ x sin 12πt

Given that the wavelength = the length of the rope, the rope is on second harmonic

L = 2·n and the length of the wire = 2 × 2 = 4 m given the dimensions are in meters

b) Where k = 2·π/λ

v = ω/k = 12π/(2·π/λ)= (12π/2π)×λ = 24 m/s

c) f = v/λ = 24/4 = 6 Hz

[tex]f = \dfrac{\sqrt{\dfrac{T}{m/L} } }{2L} = \dfrac{\sqrt{\dfrac{100}{m/4} } }{2 \times 4}[/tex]

[tex]6 \times 8= {\sqrt{\dfrac{100}{m/4} } }[/tex]

m/4 = 100/2304

m = 0.174 kg.

Answer:

External locus of control

Explanation:

External locus of control is an attitude people possess that makes them attribute their failures or successes to factors other than themselves. The opposite of this type of attitude is the Internal locus of control where the individuals take responsibility for the outcomes of their actions whether good or bad. One good thing about the external locus of control is that when the individuals with this characteristic record successes, they attribute it to others and this presents them as people with team spirit. However, when they record failures, they do not want to take the blame, but rather attribute it to others.

Fred exhibits an external locus of control because he attributed his speeding to other factors like the road signs and GPS instead of fully admitting that it was his fault.

Answer:

1. 60 m/s.

2. 3600 m.

Explanation:

The following data were obtained from the question:

Initial velocity (u) = 0

Acceleration (a) = 0.5 m/s²

Time (t) = 2 mins

Final Velocity (v) =?

Distance travelled (s) =?

1. Determination of the velocity at the end of 2 minutes.

Initial velocity (u) = 0

Acceleration (a) = 0.5 m/s²

Time (t) = 2 mins = 2 x 60 = 120 secs

Final Velocity (v) =?

v = u + at

v = 0 + (0.5 x 120)

v = 60 m/s

Therefore, the velocity at the end of 2 minutes is 60 m/s.

2. Determination of the distance travelled.

Initial velocity (u) = 0

Acceleration (a) = 0.5 m/s²

Final velocity (v) = 60 m/s

Distance travelled (s) =..?

v² = u² + 2as

60² = 0 + 2 x 0.5 x s

3600 = 1 x s

s = 3600 m

Therefore, the distance travelled is 3600 m.

Answer:

If I understand correctly. Line B is parallel to the circle. Also, the angle is less than 90.

'Circle' is characterized as "a two-dimensional geometric figure comprising of the set of all those points in a plane that are at equal distance from the center."

1). Line B would be considered as the 'tangent' in association with the given circle.

2). The angle lying among the lines A and B would be of 90° i.e. right angle.

Given that,

A circle with line A drawn through its center

Line B moves while touching the edge of the circle and intersects line A outside the circle.

Learn more about 'circle' here:

brainly.com/question/11833983

Answer:

1 Watt

Explanation:

Power (P) = w / Δt

w = work done

Δt = change in time

Power (P) = 60kg / 60 seconds

Power (P) = 1 Watt

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 the above equation

So,

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

Hence, this is the required solution.

Answer:

The limits of our senses are

Limits of Sight

Our vision field of view is 120° sideways and 135° vertically

Angular visual resolution is about an 1/60 of one degree

The presence of blind spots in the eyes

Limits of sound

The hearing range is within 20 - 20,000 Hz and our threshold hearing above 0 to 5 decibel of sound

Limits of taste

We have very limited sense of taste which is partly dependent on our sense of smell with little objectivity in distinguishing tastes

Sense of smell

The establishing of the effectiveness of human sense of smell is gauged on numerous parameters with certain tests being inconsistent, as such, it is difficult to clearly establish the effectiveness of the human sense of smell

In comparison with the sense of smell of other living things such as dogs, the human sense organ is comparatively low

Explanation:

Answer:

I suppose that by forward velocity the question refers to horizontal velocity

Since the acceleration due to gravity is 10 m/s2.The object gains an increase of 10 m/s in speed per second.In after one second its speed will be 10M/S

The direction will be downward i.e vertical

Answer:

A. velocity and time

Explanation:

A force can be define as an agent which has the capacity to change the state of an object. It can either increase the velocity of a body, change its direction of motion or cause a moving object to come to rest.

From Newton's second law of motion;

F = ma

where F is the force on the object, m is the mass of the object and a is the acceleration of the object. The unit of force is kgm/[tex]s^{2}[/tex] or Newtons.

a = [tex]\frac{change in velocity}{change in time}[/tex]

In the given question, apart from the mass of the object which is constant, the students should take the measurements of the velocity and time in each trial so as to calculate the required acceleration.

Answer:

mass and acceleration!

Explanation:

Because i am in class just like you and got it wrong because i didn't choose   my first answer:(

Answer: No

Explanation: Simply Power’s Si base unit is kgm^2s^-3 but work done‘s Si base unit is kgm^2s^-2.

So this itself proves that they arent the same!

Answer:

5 N.

Explanation:

Data obtained from the question include the following:

Mass (m) of object = 1 kg

Acceleration (a) = 5 m/s²

Force (F) =?

Force is simple defined as the product of mass and acceleration. Mathematically, it is expressed as:

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

F = ma

With the above formula, we can obtain the net force needed to accelerate the object as follow:

Mass (m) of object = 1 kg

Acceleration (a) = 5 m/s²

Force (F) =?

F = ma

F = 1 x 5

F = 5 N.

Therefore, the net force needed to accelerate the object is 5 N.

Answer:

electromagnetic wave. this energy is what lights the bulb.

Explanation:

When you close an electrical circuit, the electrons have a small drag speed, but the fluctuation of the electric field that is created originates by Lenz's law a magnetic field and the appearance of this magnetic field creates a fluctuating elective field, these two fields together forms a wave called an electromagnetic wave.

 This electromagnetic wave has a speed given by the relation

               v = √1 /ε μ

in a vacuum this speed is equal to the speed of light, which is worth 3 10⁸ m/s this very high value so the energy transported by this wave can travel the distance of 10 m in less than 10⁻⁷ s, This energy is what lights the bulb.

Answer:

Which atomic number corresponds to the element which is most stable?

01

03

28

36

36 is your answer.

Answer:

There will  be a huge problem of holding the wire strands together, and the power losses will also be amplified.

Explanation:

The force per unit length on two current carrying conductors, lying parallel to each other is proportional to the product of the current through the conductors, and inversely proportional to their distance apart. This force is attractive if the current flows through these conductors in the same direction, and is repulsive if it flows in the opposite direction.

For the strand of wire that make up a high voltage wire bundle, there will be a force of attraction pulling the wires closer to each other, and they will experience the maximum pulling force possible, since they lie next to each other. This force helps to hold these wires in a high tension wire strand together, limiting the area, and reducing "skin effect."

In the case that this wires in the wire strand acts in opposite of the known behavior, the wires will repel and push each other apart. This pushing apart will increase power loss due "skin effect" which is increased by an increase in exposed surface area of the wire strands. This will pose a big problem for high tension transmission.