A car of mass 900 Kg is moving with a velocity of 10 m/s. It is brought to rest at 25 m distance by applying the brakes. Calculate the acceleration. Why is it negative? How much force is required to stop the car?
Answer:
Assumption: the acceleration of this vehicle is constant until it comes to a stop.
Acceleration: [tex](-2)\; \rm m\cdot s^{-2}[/tex].
The acceleration of this vehicle is negative because the velocity of this vehicle is decreasing over time.
Explanation:
Let [tex]u[/tex] denote the initial velocity of this vehicle. [tex]u = 10\; \rm m\cdot s^{-1}[/tex].Let [tex]v[/tex] denote the final velocity of this vehicle. [tex]v = 0\; \rm m\cdot s^{-1}[/tex] as the vehicle has come to a stop.Let [tex]x[/tex] denote the displacement of this vehicle. [tex]x = 25\; \rm m[/tex].Let [tex]a[/tex] denote the acceleration of this vehicle. The value of [tex]a\![/tex] needs to be found.Assume that the acceleration of this vehicle, [tex]a[/tex], is constant. The SUVAT equations would apply.
The time [tex]t[/tex] required for braking is neither given nor required. Hence, make use of the SUVAT equation [tex]v^{2} - u^{2} = 2\, a\, x[/tex] to relate [tex]u[/tex], [tex]v[/tex], [tex]a[/tex], and [tex]x\![/tex].
Rearrange this equation to find an expression for [tex]a[/tex], the acceleration of this vehicle:
[tex]\begin{aligned}a &= \frac{v^{2} - u^{2}}{2\, x} \\ &= \frac{(0\; \rm m\cdot s^{-1})^{2} - (10\; \rm m \cdot s^{-1})^{2}}{2\times (25\; \rm m)} \\ &= \frac{0^{2} - 10^{2}}{2 \times 25}\; \rm m \cdot s^{-2} \\ &= -2\; \rm m\cdot s^{-2}\end{aligned}[/tex].
When the rate of change of a value is greater than [tex]0[/tex], that value would become larger over time.When the rate of change of a value is equal to [tex]0[/tex], that value would be constant.When the rate of change of a value is smaller than [tex]0[/tex], that value would become smaller over time.
Acceleration is the rate at which velocity changes over time.
The velocity of the vehicle in this question is getting smaller over time. Hence, the rate of change of the velocity of this vehicle (that is, the acceleration of this vehicle) would be a negative number.
Give reason for the following:
a) An inflated balloon was pressed against a wall after it has been rubbed with a
piece of synthetic cloth. It was found that the balloon sticks to the wall.
b) When an object is thrown up, it comes back to ground.
c) Mountaineers suffer nose bleeding at higher altitudes.
d) Foundations of high rise buildings are kept wide.
e) Deep sea divers or high altitude fliers wear special suits.
f) Walls of a dam are thickened near the base.
a) An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. This is because a positive and negative electric charge is produced, therefore the balloon sticks to the wall.
b) When an object is thrown up, it comes back to ground because of gravitational attraction force of earth.
c) Mountaineers suffer nose bleeding at higher altitudes because the oxygen level decreases with increase in altitude, which the body cannot adjust.
d) Foundations of high rise buildings are kept wide because more is the area of contact, less is the pressure efforts. So, foundations are wide so as to decrease the possibility of the building from falling down.
e) Deep sea divers or high altitude fliers wear special suits so as prevent their body from being crushed by the water pressure. Since water pressure is maximum at deep seas and oceans, therefore, more is the risk of being injured.
f) Walls of a dam are thickened near the base so that the dam can handle the kinetic energy pressure and prevent itself from breaking down, which if not, can lead to flooding.
HOPE IT HELPS...
Can someone do my physics work for $150?
Answer:
sure
Explanation:
what/where is the work
how can we use data to predict future motion
Answer:
Explanation:
How can we predict future motion?
Image result for how can we use data to predict future motion
Make observations and/or measurements of an object's motion to provide evidence that a pattern can be used to predict future motion. Clarification Statement: Examples of motion with a predictable pattern could include a child swinging in a swing, a ball rolling back and forth in a bowl, and two children on a see-saw.
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Answer:
b
Explanation:
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Calculate the sum of the following numbers to the appropriate number of significant figures.
32.567 + 135.0 + 1.4567
Answer:
The answer is 169.0.
Explanation:
For addition and subtraction problems with significant figures, the answer should be rounded to the same number of decimal places as the measurement with the least number of decimal places.
Rules for Significant Figures:
All non-zero digits are considered significant. For example, 91 has two significant figures (9 and 1), while 123.45 has five significant figures (1, 2, 3, 4, and 5).Zeros appearing between two non-zero digits (trapped zeros) are significant. Example: 101.12 has five significant figures: 1, 0, 1, 1, and 2.Leading zeros (zeros before non-zero numbers) are not significant. For example, 0.00052 has two significant figures: 5 and 2.Trailing zeros (zeros after non-zero numbers) in a number without a decimal are generally not significant. For example, 400 has only one significant figure (4).Trailing zeros in a number containing a decimal point are significant. For example, 12.2300 has six significant figures: 1, 2, 2, 3, 0, and 0. The number 0.000122300 still has only six significant figures (the zeros before the 1 are not significant). In addition, 120.00 has five significant figures since it has three trailing zeros.The number 0 has one significant figure. Therefore, any zeros after the decimal point are also significant. Example: 0.00 has three significant figures.Any numbers in scientific notation are considered significant. For example, 4.300 x 10-4 has 4 significant figures.1. What are the independent and dependent variables in each of the experiments?
Relative densoty hydrometer puridy of milk
Answer:
Hope this can help u
Explanation:
A lactometer is a specialized hydrometer used measure the relative density and purity of milk. ... If the milk is pure the readings will be close to 1 and if the amount of water in the milk increases then the markings will be close to 3.
A snail at position 3 cm moves to position 20 cm in 8 seconds
What is it's velocity ?
What is it's displacement ?
Answer:
no worries
Explanation:
Leave it to me.
Answer:
17 cm
Because the equation you're using is ∆d=df
The meters are
A-B: 60
B-C: 70
C-D: 80
D-E:20
Already answered Pythagorean on E & calculated but not sure what else to write. With the last question in E and the rest of the questions
Answer:
ab 60
Explanation:
What mass of water in grams will fill a tank 100cm long, 50cm wide, 30cm high?
Answer:
150,000grams
Explanation:
100*50*30=150,000
Also 1ml water= 1 grams
Answer:
150,000³
Process:
You multiply 100cm x 50cm x 30cm. The reason you do this is because the "mass" will be the volume of the tank of water. A "small 2" would represent a two dimensional area, whereas the "small 3" would represent a 3 dimensional area.
Worth 10 points! I will give brainliest!! Please help!!! See picture!
Answer:
The last option
Explanation:
Is the sentence "the temperature outside is 250 C." Qualitative or quantitative
Answer: Quantitative
Explanation: because quantitative is numbers
A 210 Ohm resistor uses 9.28 W of
power. How much current flows
through the resistor?
(Unit = A)
[tex]\boxed{\sf P=I^2R}[/tex]
[tex]\\ \sf\longmapsto I^2=\dfrac{P}{R}[/tex]
[tex]\\ \sf\longmapsto I^2=\dfrac{9.28}{210}[/tex]
[tex]\\ \sf\longmapsto I^2\approx0.04[/tex]
[tex]\\ \sf\longmapsto I\approx\sqrt{0.04}[/tex]
[tex]\\ \sf\longmapsto I\approx\sqrt{\dfrac{4}{100}}[/tex]
[tex]\\ \sf\longmapsto I\approx\dfrac{\sqrt{4}}{\sqrt{100}}[/tex]
[tex]\\ \sf\longmapsto I\approx\dfrac{2}{10}[/tex]
[tex]\\ \sf\longmapsto I\approx0.2A[/tex]
Answer:
.21
Explanation:
acellus
explain thermal equilibrium?
Answer:
Heat is the flow of energy from a high temperature to a low temperature. when these temperature balance out, heat stops flowing, then the system (or set of system) is said to be in thermal equilibrium.
Which of your groups should you NOT change anything for? (in other
words, everything stays the same for this group)
A.Experimental
B.Control
C.Quantitative
D.Qualitative
Answer:
B
Explanation:
The control is something that is meant to not be changed, the control is a comparison of the experimental.
How many covalent bonds is phosphorus (Group 5A) likely to form? (1 point) O five O four two three
Answer:
Three
Explanation:
Group 5A elements like phosphorus form 3 covalent bonds.
Answer: 3
Explanation:
A body weights 50 N in air and 45 N when wholly immersed in water calculate (i) the loss in weight of the body in water (ii) the upthrust on the body. (iii) volume of the body.
Answer:
[tex]difference \: in \: weight = 150n - 100n = 50n[/tex]
Now,buyantant force
[tex]difference \: in \: weight \: = volume(body) \times density \: of \: water \: \times g[/tex]
so;
[tex]50 = {v}^{b} \times 1 \times {10}^{3} \times 9.8m {s}^{2}[/tex]
[tex] {v}^{b} = \frac{50}{1000 } \times 9.8[/tex]
[tex] = \frac{50}{9800} [/tex]
[tex] = 0.0051[/tex]
Now,
[tex]mass \: in \: air \: = 150n = \frac{150}{9.8kg} [/tex]
[tex]density = \frac{weght}{volume} [/tex]
[tex] = \frac{150}{0.0051} \times 9.8 \\ x = 3000[/tex]
And now,
[tex]specific \: density \: = \frac{density of \: the \: body}{density \: of \: water} [/tex]
[tex] = \frac{3000}{1000} [/tex]
[tex] = 3[/tex]
Hence that,specific density of a given body is 3
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Two representative elements are in the same period of the periodic table. Which statement correctly describes the atoms of the two elements?(1 point)
They have the same number of valence electrons.
They have the same number of valence electrons.
They have valence electrons in different energy levels.
They have valence electrons in different energy levels.
They have valence electrons in the same energy level.
They have valence electrons in the same energy level.
They have the same number of electrons.Helium is in group 18 of the periodic table. How is helium different from the other elements in this group?(1 point)Helium atoms have valence electrons in the first energy level, while atoms of the other elements in the group have valence electrons in the second energy level.
Helium atoms have valence electrons in the first energy level, while atoms of the other elements in the group have valence electrons in the second energy level.
Helium atoms have 2 valence electrons, while atoms of the other elements in the group all have 8 valence electrons.
Helium atoms have 2 valence electrons, while atoms of the other elements in the group all have 8 valence electrons.
Helium atoms have a full outer energy level, while atoms of the other elements in the group do not have a full outer energy level.
Helium atoms have a full outer energy level, while atoms of the other elements in the group do not have a full outer energy level.
Helium atoms have 2 electrons, while atoms of the other elements in the group all have 18 electrons.
Use the periodic table to answer the question.
Which element has atoms with valence electrons in a higher energy level than those of calcium (Ca)?
lithium (Li)
lithium (Li)
cesium (Cs)
bromine (Br)
oxygen (O)
Use the periodic table to answer the question.
Which statement best describes the arrangement of electrons in an atom of fluorine (F)?
There are seven electrons in the first energy level and two electrons in the second energy level.
There are seven electrons in the first energy level and two electrons in the second energy level.
There are five electrons in the first energy level and two electrons in the second energy level.
There are five electrons in the first energy level and two electrons in the second energy level.
There are two electrons in the first energy level and seven electrons in the second energy level.
There are two electrons in the first energy level and seven electrons in the second energy level.
There are two electrons in the first energy level and five electrons in the second energy level.
Elements in the periodic table are arranged in the increasing order of their atomic number.
An atom will contain equal amount of protons and electrons. If two elements are in same period of periodic table then these elements will have same number of electrons.
Helium is one of the seven elements which are called as noble gases. This gas is odorless, tasteless and colorless which makes it unique from other elements.
It has two valence electrons while atoms of other elements in the group have 8 valence electrons.
Lithium has one valence electron, while calcium atom has 2 valence electrons.
The highest level of energy is due valence electrons of an atom. The correct answer is Lithium.
Fluorine element has 9 electrons. There are 2 electrons in the first energy level and seven electrons in the second energy level.
Learn more at https://brainly.com/question/24373385
Use the list to answer the question.
potassium, Group 1
calcium, Group 2
iodine, Group 17
neon, Group 18
Which two elements in the list would bond together based on their ionic charges?(1 point)
potassium and neon
potassium and iodine
calcium and neon
calcium and potassium
Answer: Potassium and Iodine
Explanation:
I took the quick check and it’s right.
Michael decides to do an experiment to determine which type of sock
absorbs the most sweat. Which of these describes him doing step one of the
inquiry process?
A. Michael measures the weights of six different kinds of socks
before and after he goes running,
B. Michael finds that all-polyester socks weigh 0.05 ounce more after
he runs in them.
C. Michael predicts that all-cotton socks will absorb the most sweat,
because he thinks cotton is very absorbent.
O D. Michael asks himself which of the many types of socks in his
drawer looks like it can absorb sweat most effectively.
define 1 standard meter
Explanation:
The standard meter is the length of the path travelled by the light in vacuum during a time interval of 1/299792 of a second. The meter is the length of the path travelled by light in vacuum during a time interval of 1/299792 of a second. 1 m is about 39.37 inches.
Which of the following is true about scientific laws?
Answer: Scientific theories are never proven.
Explanation:
Someone decode this please
My friend sended this he said it was a bit horror but yeah i need help with this
Answer:
what is it for
Explanation:
If an elephant has a mass of 6,000 kg,
what would its mass be on the moon?
As you just said, the elephant "... has a mass of 6,000 kg ...". It doesn't matter where.
A woman leaning over the railing of a tall bridge accidentally drops her cell phone. If
the bridge is 39.39 m high, how long will it take the phone to hit the river below the
bridge?
What is SI unit?give examples
Answer:
The system of units which is agreed by the International Conference of Scientists held in France in 1960 A.D is called SI unit.
hey!! need this asap!! will mark brainliest! thank you in advance!
Answer:
I can help for 2. and 3.
2. 12 m
3. 6 seconds
Explanation:
From my understanding of the first question you would draw a graph that would start at 0 and pass through 3,6 6,12 9,12 12,12 then the the line would go down 15,8 18,4 21,0. I cant see problem 4 hope this helps.
Calculate the sum of the following numbers to the appropriate number of significant figures.
658.0 + 23.5478 + 1345.29
cho hình vuông ABCD, tại A và C đặt các điện tích q1=q3=q. Hỏi phải đặt ở B một điện tích bằng bao nhiêu để cường độ điện trường bằng 0