The average speed of a runner in an 800 meter race was 7.0 meters per second.How long did it take the runner to complete the race?
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
A soccer ball is kicked at an angle of 40° from the ground at a speed of 30 m/s. 1. Describe which motion (horizontal of vertical) of the ball is constant and which is accelerated
2. What are the vertical and horizontal components of the ball's initial velocity? 3. For what length of time is the ball in the air assuming the ground is flat and horizontal?
4. What is the range of the ball assuming the ground is flat and horizontal?
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.
When a 200g block is placed on the piston, the volume of the gas goes from 5×10−5m3 to 4.7×10−5m3, while the pressure goes from 5.4×104Pa to 5.7×104Pa . If the surface area of the piston is 1×10−3m2 , the energy transferred to the gas due to the compression is most nearly
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
The hair shaft is made up of three layers: an __ medulla , a cortex, and an ___cuticle
- absent; colored
-Colored; absent
-inner; outer
-outer ; inner
Assertion : Human ear converts vibration with audible frequencies into electric signals. Reason : Audible sound lies in the range of 20 to 2000 Hz. *
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A)
Both assertion (A) and reason (R) are true but reason (R) is the not the correct explanation of assertion (A) Assertion (A) is true but reason (R) is false.
Assertion (A) is false but reason (R) is true.
Both Assertion and Reason is false
Light is coming from the left; which is a concave mirror? flat rectangle from the end half circle crescent crescent flipped.
Half circle crescent shape represents the shape of concave mirror which is also known as converging mirror.
What is concave 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
A machine has an efficiency of 60%. If the machine is required to overcome a load of 30N with a force of 20N, calculate its mechanical advantage?
Explanation:
eff = m.a/ v.r
m.a = L /E
30/ 20
= 1. 5
A common flea is recorded to have jumped as high as 21 cm. Assuming that the jump is entirely in the vertical direction and that air resistance is insignificant, calculate the time it takes the flea to reach a height of 7.0 cm.
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
why a body in uniform velocity is zero acceleration ?
28 points
An electric wall clock has a second hand 15 cm long. What is the radial acceleration of the tip of this hand?
A.4.25 x 10-4 m/s2
B.5.32 10-2 m/s2
C.1.64 x 10-3 m/s2
D.3.16 x 10-3 m/s2
how does a changing magnetic field affect a piece of copper wire?
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:
How can a machine be made more efficient?
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:
How is the final speed of the cart related to the pattern in the position data?
Answer:
it increases
Explanation:
The final speed of the cart increases in relation to the pattern in the position data.
What is speed?The rate at which an object moves along a path in time is defined as speed, whereas velocity is the rate and direction of movement.In other words, speed is a scalar value, whereas velocity is a vector. The symbol for velocity is v (italic), and the symbol for speed is v. (boldface). To represent average values, a bar is placed over the symbol.The ratio of an object's distance travelled (in any direction) to the time required to travel that distance. The rate at which the position of an object changes in any direction.The ratio of distance traveled to time spent traveling is defined as speed. Speed is a scalar quantity because it has only one direction and no magnitude.To learn more about velocity, refer to:
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#SPJ2
29 HELP PLEASE!!! I'LL GIVE BEAINLIST!!!
Write a paragraph using eight words from the field of science. You can use the words listed.
words:
observation
hypothesis
theory
matter
agent
experimental group
control group
temperature
particle
criteria
Answer:
observation
hypothesis
theory
matter
agent
experimental group
control group
temperature
particle
criteria
Explanation:
If you wanted to study regions where star formation is currently happening you could use: a. H-alpha emission to look for O and B stars b. 21 cm radiation to find neutral hydrogen clouds c. radio emission from carbon monoxide (CO) to find molecular cloud cores d. infrared emission to identify T Tauri stars
Whenever someone want to study regions where star formation is currently happening Infrared emission to identify T Tauri stars.
What is star-forming region?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;
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Fast food and juice boxes are example of which of these?
0 air pollution
0 water pollution
0 habitat destruction
0 overpackaging
Answer:
habitat destruction I think so
What happens when a light wave is refracted? Question 1 options: The waves spread out. The wave changes direction. The wave is scattered. The wave changes frequency.
When light wave is refracted, the wave changes direction.
What is Wave Refraction?Refraction of waves refer to the process that result in a change in waves direction as the wave is transmitted from one medium to another. Refraction of wave can be the process of bending of the path of the waves which is caused by a change in speed and wavelength of the waves.
Therefore, When light wave is refracted, the wave changes direction.
Learn more about Refraction of wave from the link below.
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please answer fully explained. don't answer for points. will mark brainlist
lighting discharge, b: stay away from tall things, and stay away from any items that conduct electricity
4–15. The post is made of Douglas fir and has a diameter of 100 mm. If it is subjected to the load of 20 kN and the soil provides a frictional resistance that is distributed along its length and varies linearly from w = 4 kN>m at y = 0 to w = 12 kN>m at y = 2 m, determine the force F at its bottom needed for equilibrium. Also, what is the displacement of the top of the post A with respect to its bottom B? Neglect the weight of the post.
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
CAN ANYONE PLS WRITE A POEM ABOUT NEON!!!!!!!!
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.
A cell phone uses a 3. 0 V battery. The circuit board it uses needs a 0. 05 A current. What size resistor is needed to generate this current? Ω.
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.
What is a resistor?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.
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Which of the following objects is in static equilibrium?
A. An apple falling from a tree
B. A car moving at a constant velocity
C. A motorcycle speeding up
D. A bicycle sitting on the ground
[tex]\longrightarrow \textsf{D. A bicycle sitting on the ground} [/tex]
Solution:-Let us check all options -
A) An apple falling from a tree is under the influence of gravity. Thus some force is acting on the apple and it can not said to be in state of equilibrium. B) A car moving at a constant velocity may said to be in state of equilibrium but the since the car is in motion ,equilibrium is dynamic in nature .Thus , it is not in static equilibrium.C) A motorcycle speeding up has some acceleration due to some forces. Thus it can also not be said in state of static equilibrium.D) Since the force acting on bicycle sitting down in zero as well as it is in state of rest , thus bicycle sitting on the ground may said to be in static equilibrium.What is the value of the charge that experiences a force of 2.4 × 10–3 n in an electric field of 6.8 × 10–5 n/c? 1.6 × 10–7 c 2.5 × 10–3 c 2.8 × 10–3 c 3.5 × 101 c
The value of the charge will be 35 ×10¹ C. A charge is something experienced as a force in the electric and megnetic field.
what is the charge?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;
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Answer:
D
Explanation:
E2020
how do you balance
___Ca + __O2 → ___CaO
Answer:
2Ca+ O2 ------> 2CaO
mark me as brainiest
A car of mass 1500kg is brought to rest from a velocity of 25m/s by a constant force of 3,000N. Determine the change in momentum produced by the force and the time it takes for the car to come to rest.
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
what is the acceleration of the Tesla Model S in m/s²?
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:
Why do tin roofs make creaking sounds on hot days?
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
What is the acceleration of a mongoose that, if from rest, can reach
speeds of 19 ft/s in 8.8 seconds?
O 2.25 s
O 174.24 ft/s/s
2.25 ft/s/s
2.25 m/s
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
what is illuminance
Answer:
The amount of luminous flux per unit area
Explanation:
Para levantar del suelo una caja metálica de 50 Kg se emplea maquinaria que utiliza un cable inextensible e imprime una aceleración de 0,8 m/seg2. ¿Qué tensión soporta el cable y qué tiempo le tomará a la máquina levantar la caja a una altura de 10 metros? Lo necesito urgente
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