A car accelerates from rest at 7.2 m/s 2 . How much time does it need to attain a speed of 4 m/s? Answer in units of s.
Answer:
The time is 0.6 sec.
Explanation:
Given that,
Acceleration of car = 7.2 m/s²
Speed = 4 m/s
We need to calculate the time
Using equation of motion
[tex]v=u+at[/tex]
Where, u = initial velocity
v = final velocity
a = acceleration
t = time
Put the value in the equation
[tex]4=0+7.2\times t[/tex]
[tex]t=\dfrac{4}{7.2}[/tex]
[tex]t=0.6\ sec[/tex]
Hence, The time is 0.6 sec.
55. A dog starts at the origin and runs forward at 6 m/s for
1.5 s and then turns around to fetch the ball by
running backward at 7 m/s for 3 s. If the dog runs
back to the origin at 4 m/s, then how much time has
elapsed between the start and when he returns with
the ball?
0-
Position vs. time
61
-5
-10
Position (m)
-15
-20
-250
0.2
0.8
1.0
1.2
0.4 0.6
Time (s)
Answer:
7.5 seconds
Explanation:
Given that a dog starts at the origin and runs forward at 6 m/s for 1.5 s
From speed formula
Speed = distance/time
Substitute speed and time into the formula
6 = distance/1.5
Distance = 6 × 1.5 = 9 m
and then turns around to fetch the ball by
running backward at 7 m/s for 3 s. If the dog runs.
Calculate the distance covered
Distance = 7 × 3 = 21 m
This means that the dog ran beyond the original position.
The elapsed distance = 21 - 9 = 12m
back to the origin at 4 m/s, by covering distance 12 m
Calculate the time.
Speed = distance/time
Time = 12/4 = 3s
The time elapsed between the start and when he returns with the ball will be:
T = 1.5 + 3 × 3
T = 7.5 seconds
Sal sprints 40 m to the right in 5.5s.
What was his average velocity in m/s?
Answer:
7.27 m/s
Explanation:
You would be dividing 40 (distance) by 5.5 (time) to get the average velocity of 7.27 m/s .
Answer:
7.27
Explanation:
40/5.5=7.27
In 1993, Ileana Salvador of Italy walked 3.0 km in under 12.0 min. Suppose that during 115 m of her walk Salvador is observed to steadily increase her speed from 4.20 m/s to 5.00 m/s. How long does this increase in speed take?
Answer:
t = 25 seconds
Explanation:
Given that,
Distance, d = 115 m
Initial speed, u = 4.2 m/s
Final speed, v = 5 m/s
We need to find the time taken in increasing the speed.
We know that,
Acceleration, [tex]a=\dfrac{v-u}{t}[/tex] ....(1)
The third equation of kinematics is as follows :
[tex]v^2-u^2=2ad\\\\\text{Put the value of a in above equation}\\\\v^2-u^2=2\times \dfrac{v-u}{t}\times d\\\\\because (a^2-b^2)=(a-b)(a+b)\\\\(v-u)(v+u)=\dfrac{2\times (v-u)d}{t}\\\\t=\dfrac{2d}{v+u}\\\\\text{Putting all the values}\\\\t=\dfrac{2\times 115}{4.2+5}\\\\t=25\ s[/tex]
Hence, it will take 25 seconds to increase the speed.
During a sunny afternoon, the sun suddenly seems much less bright than usual. The daylight seems much less intense, as if there is a dense cloud cover, but there’s no clouds in the sky. After about half an hour, everything seems normal again. Which claim about the temporary decrease in light can be supported by the evidence?
Answer:
D). A sudden change in temperature increased the density of the atmosphere.
Explanation:
The claim that can be made and supported with evidence regarding the temporary decrease in light would be 'a sudden change in temperature will increase the density of the atmosphere.' As the temperature increases, the molecules in the atmosphere begin to move fastly which causes a decrease in atmosphere density while it increases with the fall in temperature. As a result, the intensity of sunlight gets affected due to molecules being heavier and floating in the atmosphere. Thus, option D is the correct answer.
Answer: Its the atmosphere
Explanation:
I have had this Question before. hope this helps:)
A ball is thrown straight up. If the launch velocity is 15 m/s, at what SPEED will the ball return to the thrower’s hand?
a) -15 m/s
b) -9.8 m/s
c) 15 m/s
d) 0 m/s
Answer:
Vf = 15 m/s
Explanation:
First we consider the upward motion of ball to find the height reached by the ball. Using 3rd equation of motion:
2gh = Vf² - Vi²
where,
g = acceleration due to gravity = -9.8 m/s² (negative sign for upward motion)
h = height =?
Vf = Final Velocity = 0 m/s (Since, ball momentarily stops at highest point)
Vi = Initial Velocity = 15 m/s
Therefore,
2(-9.8 m/s²)h = (0 m/s)² - (15 m/s)²
h = (-225 m²/s²)/(-19.6 m/s²)
h = 11.47 m
Now, we consider downward motion:
2gh = Vf² - Vi²
where,
g = acceleration due to gravity = 9.8 m/s²
h = height = 11.47 m
Vf = Final Velocity = ?
Vi = Initial Velocity = 0 m/s
Therefore,
2(9.8 m/s²)(11.47 m) = Vf² - (0 m/s)²
Vf = √(224.812 m²/s²)
Vf = 15 m/s
I need this now due date 9-11-20 1:00pm
Answer:
Yes because the hotter the water the less time it takes to dissolve.
Explanation:
Please help on this physics question
Answer:
you need to include the units for both axis to be able to answer this
Explanation:
average speed in uniform motion is the slope anywhere on the line but you could always pick 2 points and do it that way and speed is just rise over run
or y2-y1/x2-x1
Pick two points on the line and determine their coordinates.
Determine the difference in y-coordinates of these two points (rise).
Determine the difference in x-coordinates for these two points (run).
Divide the difference in y-coordinates by the difference in x-coordinates (rise/run or slope).
the second bit i think they are looking for this calculation y = mx + b, where m is the slope and b is the y-intercept (where the line crosses the y axis (the vertical one that has no units
Then use that formula for the last question and put in the x value of 10 and complete the formula to find out what y is
how far will a skateboard travel in 30 seconds if traveling at a speed of 3 m/s
Is velocity constant in uniform motion?
The Direction of the Velocity Vector
Objects moving in uniform circular motion will have a constant speed. Velocity, being a vector, has both a magnitude and a direction. The magnitude of the velocity vector is the instantaneous speed of the object.
A coin is dropped from the top of the Tower of Pisa, 53m above the ground. What is the coin's initial velocity?
Answer:
Initial velocity U = 0
Final velocity V = 32.23 m/s
Explanation:
Given that a coin is dropped from the top of the Tower of Pisa, 53m above the ground.
What is the coin's initial velocity ?
Since the coin is dropped from the tower, the initial velocity U will be equal to zero.
Therefore, U = 0
But the final velocity V will be calculated by using the formula
V^2 = U^2 + 2gH
V^2 = 0 + 2 × 9.8 × 53
V^2 = 1038.8
V = sqrt ( 1038.8)
V = 32.23 m/s
Describe three common issues that affect societies across places and times
Answer
Common issues that affect societies across places and times include healthcare, disease, natural disasters, drought, unemployment, racism, war, pollution, over-use of resources, selecting leaders, high taxes, education, and relationships with other countries.
When the mass of an object decreases, the force of gravity - Remains Unchanged - Decreases - increases - Becomes irregular
Answer:
Decreases
Explanation More mass=More gravitational pull
Less mass=Less gravitational pull
Hope this helps
Answer:
decreses
Explanation:
hey can anyone pls help me out in dis !
All of the above.
For example:
A glass plate is a solid. Particles vibrate in a solid and are closely packed. together.
It doesn’t change shape if you touch it.
It doesn’t change volume like it’s water.
Answer:
D: all of the above
Explanation:
particles in a solid do vibrate but they're tightly packed and move around fixed location
difference between weightlessness in space and weightlessness in earth
In space we feel weightlessness because the earth's gravity has less effect on us. The Earth's gravitational attraction at those altitudes is only about 11% less than it is at the Earth's surface. If you had a ladder that could reach as high as the shuttle's orbit, your weight would be 11% less at the top.
Question 2 of 10
Which statement best describes how vomiting can help an animal maintain
homeostasis?
A. It keeps the animal's body temperature within a certain range.
B. It rids the body of something harmful.
C. It prompts the animal to eat healthy food.
D. It uses up excess energy in the body.
Answer:
I would say B. It rids the body of something harmful.
Explanation:
Vomiting usually tries to get rid of something bad in your stomach. If you vomit when your sick its because its trying to get rid of that sickness.
Hope this helps >:3
Answer:
B. It rids the body of something harmful.
Explanation:
A swimming pool is an example of an open system. The pool loses 10,500 J
of its thermal energy to the surrounding air at night, and the surrounding air
adds 2,500 J of thermal energy to the pool in the morning. According to the
law of conservation of energy, what is the total change in energy?
Answer: A a decrease of 8000
Explanation: 10,500 - 2,500= 8000
Answer:
Its A
Explanation: Sure
Which option lists a form of potential energy followed by a form of kinetic energy?
A. Sound energy | nuclear energy
B. Magnetic energy electromagnetic energy
C. Gravitational energy | elastic energy
D. Electromagnetic energy | electrical energy
Answer:
Magnetic energy and electromagnetic energy form of potential energy followed by a form of kinetic energy.
(B) is correct option.
Explanation:
Given that,
Lists a form of potential energy followed by a form of kinetic energy
We know that,
Sound energy :
The movement of energy through object it is called sound energy. When a object produced vibration by force then it moves in wave.
Sound wave is example of kinetic energy.
Nuclear energy :
The store energy in the nucleus of the atom it is called nuclear energy. This energy released when occurs fusion and fission.
Nuclear energy is the example of potential energy
Magnetic energy :
Magnetic energy is a type of potential energy which is depend on distance and position in the magnetic field.
Electromagnetic energy :
Electromagnetic energy is light energy. it is type of kinetic energy.
Gravitational energy :
Gravitational energy is a type of potential energy. It is an energy related with gravity or gravitational force.
Elastic energy :
The store energy in elastic object it is called elastic energy. This energy is a type of potential energy.
Electrical energy :
The movement of electrons is called electrical energy. When electrons move through a wire then it is are called electricity. Electrical energy is type of kinetic energy.
Hence, Magnetic energy and electromagnetic energy form of potential energy followed by a form of kinetic energy.
(B) is correct option.
Answer:
its B
Explanation:
PLS HELP. A flatbed car of a train moves 8 m/s to the east. A jogger runs along to top the flatbed car (which is not very safe) with a velocity of 6 m/s to the west. How fast is the jogger moving?
Answer:
2 m/s
Explanation: Given that a flatbed car of a train moves 8 m/s to the east. A jogger runs along to top the flatbed car (which is not very safe) with a velocity of 6 m/s to the west.
Since the jogger is moving in an opposite direction to the direction of the train, and velocity is the distance covered in a specific direction, the jogger will be moving at a velocity relative to the velocity of the train.
Velocity = (8 - 6) m/s
Velocity = 2 m/s
Therefore, the jogger will be moving at the speed of 2 m/s
6.P.2.1 Matter: Properties and Changes Notes
The Theory ______
of Conservation
of
states:______
cannot be
or!____________
height
is anything that has
(weight) and height
(takes up space).
A
is the
in an object.
is the
an object takes
to add speaker notes
Answer:
The __law__ conservation
of state that either energy may produced nor destroyed
What does amu represent?
The figure shows a horizontal pipe with a circular cross section whose diameter varies. The cross-sectional area at X is 3.0×10−4m2 and at Y is 0.60×10−4m2. Water of density 1000kg/m3 fills the pipe and flows through it at a constant rate of 2.4×10−4m3/s. The difference in pressure between X and Y is most nearly 750 Pa 750 Pa A 1600 Pa 1600 Pa B 7700 Pa 7700 Pa C 8320 Pa 8320 Pa D
By Bernoulli's Principle :
[tex]P_x+\dfrac{\rho v_x^2}{2}+\rho gz_x=P_y+\dfrac{\rho v_y^2}{2}+\rho gz_y[/tex]
Since , pipe is horizontal so every point is at same height .
So , [tex]z_x=z_y[/tex] .
The equation will reduced to :
[tex]P_x+\dfrac{\rho v_x^2}{2}=P_y+\dfrac{\rho v_y^2}{2}[/tex] ..... 1 )
Also flow rate will be constant :
[tex]Q=A_xv_x=A_yv_y[/tex]
[tex]v_x=\dfrac{Q}{A_x}\\\\v_x=\dfrac{2.4\times 10^{-4}}{3\times 10^{-4}}\ m/s\\\\v_x=0.8\ m/s[/tex]
[tex]v_y=\dfrac{Q}{A_y}\\\\v_y=\dfrac{2.4\times 10^{-4}}{0.6\times 10^{-4}}\ m/s\\\\v_x=4\ m/s[/tex]
Now ,
[tex]P_x-P_y=\dfrac{\rho v_y^2}{2}-\dfrac{\rho v_x^2}{2}\\\\P_x-P_y=\rho[\dfrac{ v_y^2}{2}-\dfrac{v_x^2}{2}]\\\\P_x-P_y=1000\times [\dfrac{ 4^2}{2}-\dfrac{0.8^2}{2}]\\\\P_x-P_y=7680\ Pa[/tex]
Difference in pressure between X and Y is most near to 7700 Pa.
Hence, this is the required solution.
A ray of light strikes a plane mirror at an angle of incidence of 60°, is reflected from the mirror and then strikes a second plane mirror placed so that the angle beftween the mirrors is 45°. The angle of reflection at the second mirror, in degrees, is
A 15
B 25
C 45
D 65
E 75
plz help me guys ASAP!
Answer:
60 - 45 = A. 15
Explanation:
Subtracted because the plane mirror at an angle is incidence of 60°, so then in order to find the value it would be 60-45 and not adding it or dividing and multiplying to find the value thus the answer is 15.
60 - 45 = A. 15. Subtracted because the plane mirror at an angle is incidence of 60°, so then in order to find the value it would be 60-45 and not adding it or dividing and multiplying to find the value thus the answer is 15.
What is Plane mirror?A flat or highly polished surface called a plane mirror reflects light or waves to create an image. It is a polished, smooth surface that creates a virtual representation of the actual object.
A plane mirror is a surface on which an image can only be produced by at least two light beams. The intersection of these two beams can occur inside the mirror or appear to occur somewhere behind the mirror.
The image that follows illustrates how an object appears when viewed via a plane mirror.
Therefore, 60 - 45 = A. 15. Subtracted because the plane mirror at an angle is incidence of 60°, so then in order to find the value it would be 60-45 and not adding it or dividing and multiplying to find the value thus the answer is 15.
To learn more about Plane mirror, refer to the link:
https://brainly.com/question/13101215
#SPJ2
Select the positive statement that would BEST counteract this negative statement: "I do not have the time to exercise." A. I can exercise anywhere. B. I have to start somewhere. C. I will make it a priority. D. I will increase my energy. Please select the best answer from the choices provided. A B C D
Answer:The awnser would be C!
Explanation:
Hope this helped!
Answer:
C. I will make it a priority.
Explanation:
define liquid in matter
Answer:
A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. A liquid is made up of tiny vibrating particles of matter, such as atoms, held together by intermolecular bonds.
In the lab, you looked at speed-time graphs to determine the acceleration of the cart for each of the three fan
speeds.
What was the acceleration of the cart with Low fan speed?
cm/s2
What was the acceleration of the cart with Medium fan speed? cm/s2
What was the acceleration of the cart with High fan speed?
cm/s2
Answer:
(I). The acceleration of the cart with low fan speed is 18 cm/s²
(II). The acceleration of the cart with medium fan speed is 23.3 cm/s²
(III). The acceleration of the cart with high fan speed is 32 cm/s²
Explanation:
Given that,
You looked at speed-time graphs to determine the acceleration of the cart for each of the three fan speeds in the lab.
According to graph,
A , B and shows the high, medium and low fan speeds respectively.
We know that,
The speed-time graph shows the acceleration.
Acceleration is equal to the rate of change of velocity.
(I). We need to calculate the acceleration of the cart with low fan speed
Using formula of acceleration
[tex]a_{l}=\dfrac{v_{f}-v_{i}}{t_{f}-t_{i}}[/tex]
Put the value from graph
[tex]a_{l}=\dfrac{125-0}{7}[/tex]
[tex]a_{l}=18\ cm/s^2[/tex]
(II). We need to calculate the acceleration of the cart with medium fan speed
Using formula of acceleration
[tex]a_{m}=\dfrac{v_{f}-v_{i}}{t_{f}-t_{i}}[/tex]
Put the value from graph
[tex]a_{m}=\dfrac{140-0}{6}[/tex]
[tex]a_{m}=23.3\ cm/s^2[/tex]
(III). We need to calculate the acceleration of the cart with high fan speed
Using formula of acceleration
[tex]a_{h}=\dfrac{v_{f}-v_{i}}{t_{f}-t_{i}}[/tex]
Put the value from graph
[tex]a_{h}=\dfrac{160-0}{5}[/tex]
[tex]a_{h}=32\ cm/s^2[/tex]
Hence, (I). The acceleration of the cart with low fan speed is 18 cm/s²
(II). The acceleration of the cart with medium fan speed is 23.3 cm/s²
(III). The acceleration of the cart with high fan speed is 32 cm/s²
Answer:
18.0, 24.0, 32.0
Explanation:
just did it
The density of water is 1.00 g/mL. This means if a rock has a density of 0.87 g/mL, it will ____in water.
a) float
b) sink
Answer:
Float
Explanation:
It is given that,
The density of water is 1 g/mL
The density of a rock is 0.87 g/mL
It can be seen that the density of water is more than that of rock. The density of an object is calculated from its mass and volume.
If the density of liquid in which it is placed, is more that that of the object, it will float at the top.
Hence, in this case the rock will float.
QUESTION: Is there a relationship between height and shoe size? Write a one sentence
summary of your graph.
J
Answer:
There is no particular relationship between the height and shoe size. But the shoe sizes in males is usually bigger than females. And the shoe size tends to get bigger when the person is taller.
Explanation:
2. Convert 750 m/s to km/hr.
Answer:
2700
Explanation:
1m/s=3.6km/hr
why do you think scientists put their results in data tables and graphs?
Answer:Since most of the data scientist collect is quantitative, data tables and charts are usually used to organize the information • Graphs are created from data tables • They allow the investigator to get a visual image of the observations, which simplifies interpretation and drawing
Have a nice day (^-^) ;)