Please help me answer this science question.
A.) 1
B.) 2
C.) 3
D.) 4
Thank you!
Grade: 6/middle school
Subject: Science
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Answer:

t = 0.12 s

Explanation:

Applying the second equation of motion under free fall,

h = ut + [tex]\frac{1}{2}[/tex]g[tex]t^{2}[/tex]

where: h is the height, u is its initial velocity, t is the time taken and g is the gravitational force.

But, u = 0 m/s, h = 21 cm (0.21 m) and g = 9.8 m/[tex]s^{2}[/tex]. Then:

0.21 = 0 + [tex]\frac{1}{2}[/tex] x 9.8 x [tex]t^{2}[/tex]

0.21 = 4.9[tex]t^{2}[/tex]

[tex]t^{2}[/tex] = [tex]\frac{0.21}{4.9}[/tex]

  = 0.04286

⇒ t = 0.2070

      = 0.21 s

The time taken for the flea to jump as high as 21 cm is 0.21 s.

The time taken for the flea to reach a height of 7.0 cm (0.07 m) can be determined as;

h = ut +  [tex]\frac{1}{2}[/tex]g[tex]t^{2}[/tex]

0.07 =  0 + [tex]\frac{1}{2}[/tex] x 9.8 x [tex]t^{2}[/tex]

0.07 =  4.9[tex]t^{2}[/tex]

[tex]t^{2}[/tex] = [tex]\frac{0.07}{4.9}[/tex]

  = 0.01429

t = 0.1195

 = 0.12 s

Answer:

T = 530 N ,     t = 12.65 s

Explanation:

This is an exercise on Newton's second law,

           T - W = m a

where T is the tension of the cable, W the weight and the steel of the box

            T = W + ma

the weight of a body is

            W = m g

Let's replace

          T = m g + ma

          T = m (g + a)

let's calculate

          T = 50 (9.8 + 0.8)

          T = 530 N

To calculate the time we use

          y = v₀t + ½ a t²

since the box starts from rest on the sole its initial velocity is zero

          y = ½ a t2

           t = √ 2y / a

let's calculate

          t = √ (2 10 / 0.8)

         t = 12.65 s

TRASLATE

Este es un ejercicio de la segunda ley de Newton,

           T – W = m a

donde T es la tension del cable, W el peso y a la aceracion de la caja

            T = W + ma

el pesode un cuerpo es

            W = m g      

Substituyamos

          T = m g + ma

          T = m ( g +a)

calculemos

          T = 50 ( 9,8 + 0,8)

          T = 530 N

Para calcular el tiempo usamos

          y = v₀t + ½ a t²

como la caja parte del reposo en el suela su velocidad inicial es cero

          y=   ½ a t²

           t= √ 2y/a

calculemos

          t = √ (2 10/0,8)

         t = 12,65 s

Answer: When you change the direction of the current, you also change the direction of the magnetic field. Because the magnetic field created by the electric current in the wire is changing directions around the wire, it will repel both poles of the magnet by bending away from the wire.

Explanation:

Explanation:

eff = m.a/ v.r

m.a = L /E

30/ 20

= 1. 5

Half circle crescent shape represents the shape of concave mirror which is also known as converging mirror.

A concave mirror which also called converging mirror, has a reflecting surface that goes inward. Concave mirrors are used to focus light so we can conclude that Half circle crescent shape represents the shape of concave mirror  and also known as converging mirror.

Learn more about concave here: https://brainly.com/question/198518

Answer:

the answer is C

Explanation:

just got it right hope this helps! :D

Answer: Tesla’s Model S Performance is the fastest-accelerating production car. The luxury sedan reaches 60 mph in just 2.4 seconds, which outperforms every supercar available today.

Explanation:

The value of resistance will be 60 ohms. Resistance is the opposition force offered to the flow of electric current. The ratio of the voltage to the electric current passing through the wire.

A resistor is a two-terminal passive electrical component that acts as a circuit element by implementing electrical resistance.

Resistors are used to limit current flow, alter signal levels, divide voltages, bias active devices, and complete transmission lines in electronic circuits.

The given data in the problem is;

V is the voltage =  3. 0 V

I is value of electric current=  0. 05 A

R is the resistance=?

According to ohm's law, the potential difference between the two ends of the conductor is equal to the product of electric current and the resistance generated.

So from the ohm law;

V= IR

[tex]\rm R = \frac{V}{I} \\\\ \rm R = \frac{3}{0.05} \\\\ \rm R =60 \ ohm[/tex]

Hence the value of resistance will be 60 ohms.

To learn more about the resistor refer to the link;

brainly.com/question/1322424

Answer:

habitat destruction I think so

Answer: Yes, on many slate-roofed homes as temperatures change, such as cooling at night or heating during the day, thermal expansion or contraction of the slates may cause movement that in turn causes snapping, popping, or cracking noises, even bangs and clanks or clicks from the roof.

Explanation:

Answer:

because of its mealting

Explanation:

hope it helps you

Whenever someone want to study regions where star formation is currently happening Infrared emission to identify T Tauri stars.

A star-forming region  serves as a  region of the celestial sphere where predominately young stellar objects can be found and  where formation is likely occurring.

Infrared emission to identify T Tauri stars can be used in determining the formation, however it should be noted that Einstein X-ray Observatory made earliest detections of X-rays from T Tauri stars.

Learn more about star-forming region at;

https://brainly.com/question/25898149

Explanation:

Acceleration is change in velocity over time.

a = Δv / Δt

a = (19 ft/s − 0 ft/s) / 8.8 s

a = 2.16 ft/s/s

Given parameters:

Initial velocity  = 0m/s

Final velocity = 19ft/s

Time taken  = 8.8s

Unknown:

Acceleration

Solution:

Acceleration is the change in velocity with time of a body;

                 Acceleration  = [tex]\frac{v - u}{t}[/tex]

v is the final velocity

u is the initial velocity

t is the time taken

    input the parameters and solve;

              Acceleration = [tex]\frac{19 - 0}{8.8}[/tex]  = 2.16ft/s

Now, the acceleration is 2.16ft/s

Answer:

(1).  This motion is projectile motion.

(2). The horizontal initial velocity is 19.3 m/s.

The vertical initial velocity is 22.9 m/s.

(3). The time is 3.9 sec.

(4). The range of the ball assuming the ground is flat and horizontal is 90.4 m.

Explanation:

Given that,

Angle = 40°

Velocity = 30 m/s

(1). A soccer ball is kicked at an angle from the ground at a speed of 30 m/s.

So, this motion will be projectile motion.

(2). We need to calculate the vertical and horizontal components of the initial velocity of the ball

Using formula of  vertical initial velocity

[tex]u_{y}=u\cos\theta[/tex]

Put the value into the formula

[tex]u_{y}=30\cos40[/tex]

[tex]u_{y}=22.9\ m/s[/tex]

Horizontal initial velocity ,

[tex]u_{x}=u\sin\theta[/tex]

Put the value into the formula

[tex]u_{x}=30\sin40[/tex]

[tex]u_{x}=19.3\ m/s[/tex]

(3). We need to calculate the time

Using formula of time

[tex]t=\dfrac{2u\sin\theta}{g}[/tex]

Put the value into the formula

[tex]t=\dfrac{2\times19.3}{9.8}[/tex]

[tex]t=3.9\ sec[/tex]

(4). We need to calculate the range of the ball assuming the ground is flat and horizontal

Using formula of range

[tex]R=\dfrac{v^2\sin2\theta}{g}[/tex]

Put the value into the formula

[tex]R=\dfrac{30^2\sin80}{9.8}[/tex]

[tex]R=90.4\ m[/tex]

Hence, (1).  This motion is projectile motion.

(2). The horizontal initial velocity is 19.3 m/s.

The vertical initial velocity is 22.9 m/s.

(3). The time is 3.9 sec.

(4). The range of the ball assuming the ground is flat and horizontal is 90.4 m.

Answer:

it increases

Explanation:

The final speed of the cart increases in relation to the pattern in the position data.

To learn more about velocity, refer to:

https://brainly.com/question/24445340

#SPJ2

answer:

change in momentum = 37,500kg.m/s in the opposite direction

time it takes = 12.5s

working:

u=25m/s

v=0m/s

F=ma

-3000=(1500)(a)

-3000÷1500=a

a= -2m/s^2

Change in momentum=mv-mu

(1500)(0)-(1500)(25)

= -37,500kg.m/s

relax the( - ) represents direction

v=u-at

0=25-2t

2t=25

t= 12.5s

lighting discharge, b: stay away from tall things, and stay away from any items that conduct electricity

The value of the charge will be 35 ×10¹ C. A charge is something experienced as a force in the electric and megnetic field.

When the matter is put in an electromagnetic field, it has an electric charge, which causes it to experience a force. A positive or negative electric charge can exist.

Charges that are similar repel each other, whereas charges that are dissimilar attract each other. The term "neutral" refers to an item that has no net charge.

The given data in the problem is;

F is the electric force= 2.4 × 10-³ N

q is the electric charge=?

E is the strength of the electric field = 6.8 × 10⁻⁵ (N/C)

The electric force is given by;

[tex]\rm F =qE \\\\ \rm q= \frac{F}{E} \\\\ \rm q= \frac{2.4 \times 10^{-3}}{6.8 \times 10^{-5}} \\\\ \rm q=35 \times 10^1 \ C[/tex]

Hence the value of the charge will be 35 ×10¹ C

To learn more about the charge refer to the link;

https://brainly.com/question/24391667

Answer:

D

Explanation:

E2020

Answer:

3

Explanation:

i took the quiz

Answer:

114.29s

Explanation:

average speed = distance/Time

Given

speed = 7m/s

distance = 800m

Required

Time taken by the runner to complete the race

From the formula:

Time = Distance/speed

Time = 800/7

Time = 114.29seconds

Hence it took the runner 114.29s to complete the race

Answer:

The amount of luminous flux per unit area

Explanation:

Answer:

The energy transferred to the gas is 9 mJ

Explanation:

Given;

initial volume of the gas, v₁ = 5 x 10⁻⁵ m³

final volume of the gas, v₂ = 4.7 x 10⁻⁵ m³

initial pressure of the gas, P₁ = 5.4 x 10⁴ Pa

final pressure of the gas, P₂ = 5.7 x 10⁴ Pa

The work done in compressing the gas is given by;

W = ΔPV = (P₂ - P₁)(V₂ - V₁)

W = (5.7 x 10⁴ Pa - 5.4 x 10⁴ Pa)(4.7 x 10⁻⁵ m³ - 5 x 10⁻⁵ m³)

W = (3000)( -3 x 10⁻⁶)

W = - 9  x 10⁻³ J

W = -9 mJ

Thus, the work done in compressing this gas is equal to the energy transferred to the gas = 9 mJ

[tex]\longrightarrow \textsf{D. A bicycle sitting on the ground} [/tex]

Let us check all options -

Answer:

observation

hypothesis

theory

matter

agent

experimental group

control group

temperature

particle

criteria

Explanation:

Colors so bright

They catch your eye

You can see them from miles away

They shine in the night

Such beauty from dye

Oh so many ways they can array

litterly just got this off the top of my head. it was fun making.

The image of the Douglas fir post is missing, so i have attached it.

Answer:

-0.00025918 mm

Explanation:

We are given the points it passes through as;

(y1, w1) = (0, 4)

(y2, w2) = (2, 12)

Thus, the slope is;

K = (w2 - w1)/(y2 - y1)

K = (12 - 4)/(2 - 0)

K = 8/2

K = 4

Now, substituting one of the points into the slope equation, we have;

w - w1 = k(y - y1)

w - 4 = 4(y - 0)

w = 4y + 4

For us to now find the total force the distributed load applies to the body, we will integrate to give;

W(y) = ∫w•dy

Thus;

W(y) = ∫(4y + 4)dy

W(y) = 2y² + 4y

So, the value of this force which is at y = 2 m will be;

W(2) = 2(2²) + 4(2)

W(2) = 16 KN

Now, at equilibrium, we sum up the forces in the vertical y-direction to give;

W - 20 + F = 0

F = 20 - W

F = 20 - 16

F = 4 KN

If we cut through the body to get a free body diagram and sum forces in y-direction to zero, the displacement of the top of the post A with respect to its bottom B is;

δ_B/A = [(L, 0∫)(W - 20)dy]/AE

Where A is πr²

We are given diameter = 100 mm

So, radius = 100/2 = 50 mm = 0.05 m

Also, from tables the Young's modulus of Douglas fir is 13.1 GPa or 13.1 × 10^(9) Pa

Thus;

δ_B/A = [(2, 0∫)(2y² + 4y - 20)dy]/(π × 0.05² × 13.1 × 10^(9))

δ_B/A = [((2 × 2³/3) + (2 × 2²) - 20(2)) - 0] /(0.102887 × 10^(9))

δ_B/A = (16/3 + 8 - 40)/(0.102887 × 10^(9))

δ_B/A = -0.00000025918 m = -0.00025918 mm

Answer:

Because all machines lose input work to friction, one way to improve the efficiency of a machine is by reducing friction.    Hope this helped :))

Explanation: