Answer:
B. low melting points and low densities
Explanation:
Alkali metals are any of the monovalent elements found in Group IA of the periodic table. They readily lose their one valence electron to form ionic compounds with nonmetals. Examples of alkali metal are Potassium (K), Lithium (L), and Sodium (Na).
Compared to most other metals, the chemical properties that alkali metals have are low melting points (28.5°C) and low densities that is typically less than 1 grams per cubic centimeters.
Select the correct answer.
Which quantity is a vector quantity?
ОА. .
acceleration
OB.
mass
OC.
speed
O D.
volume
Reset
Next
Answer:
acceleration is the vector quantity because it depends on particular direction and has magnitude
Object A has twice the mass of object B. Both objects are moving at the same speed. Which accurately describes how inertia relates to Newton’s second law of motion in this example? Object A has twice the mass of object B. Both objects are moving at the same speed.
A. Object A requires twice the force to stop as Object B.
B. Object A requires one-and-a-half times the force to stop as Object B.
C. Object A requires four times the force to stop as Object B.
Answer:
A. Object A requires twice the force to stop as Object B.
Explanation:
Inertia can be defined as the tendency of an object or a body to continue in its state of motion or remain at rest unless acted upon by an external force.
Newton's Second Law of Motion states that the acceleration of a physical object is directly proportional to the net force acting on the physical object and inversely proportional to its mass.
Mathematically, it is given by the formula;
[tex] Acceleration = \frac {Net \; force}{mass} [/tex]
Let's assume the following values;
Mass of object B = 10 kg
Mass of object A = 2 * B = 2 * 10 = 20 kg
Acceleration = 5 m/s²
I. To find the force for B;
[tex] Force = mass * acceleration [/tex]
[tex] Force = 10 * 5 [/tex]
Force B = 50 Newton
II. To find the force for A;
[tex] Force = mass * acceleration [/tex]
[tex] Force = 20 * 5 [/tex]
Force A = 100 Newton
From the calculation, we can deduce that Force A (100 N) is twice or double the value of Force B (50 N).
In conclusion, since object A has twice the mass of object B and both objects are moving at the same speed, object A would require twice the force to stop as Object B.
Which type of radiation can reach the furthest?
A. Beta
B. Gamma
C. Alpha
Answer:
B. Gamma
Explanation:
The gamma radiation can travel much farther through air than alpha or beta.
Explain hydraulic machine as force multiplier.
Answer:
The pressure on piston 1 is always equal to the pressure on piston 2. ... It is equal to the force on piston 1, multiplied by A2/A1. Hydraulic systems are called force multipliers for exactly this reason. A small force can be increased by using hydraulics
Explanation:
Radhe Radhe❤
Ball X has a mass of 8kg and is moving toward ball Y (which is sitting still) at 2m/s. After they collide, ball X is
sitting still. How fast is ball Y moving after the collision if it has a mass of 4kg?
Answer:
v = 4 m/s
Explanation:
Given :
Ball X :
Mass, m1 = 8kg ;
Initial Velocity, u1 = 2 m/s
Final velocity, v1 = 0
Ball Y:
Mass, m2 = 4kg ;
Initial Velocity, u2 = 0 m/s
Final velocity, v2 = v
(m1u1 + m2u2) = (m2v2 + m1v1)
(8*2 + 4*0) = (4*v + 4*0)
16 + 0 = 4v + 0
16 = 4v
v = 16 / 4
v = 4 m/s
Answer:
Explanation:
This is the Law of Momentum Conservation which for us looks like this:
[tex][m_xv_x+m_yv_y]_b=[m_xv_x+m_yv_y]_a[/tex] and that should look familiar to you if this is what you are doing in physics. Filling in our particular info:
[(8.0 × 2.0)+ (4.0 × 0.0)] = [(8.0 × 0.0) + (4.0v)] and
16 + 0 = 0 + 4.0v and
16 = 4.0v so
v = 4.0 in the direction of ball X
mechanical energy that has been "lost" to friction has actually been destroyed.
Answer:
Yes
Explanation:
The friction is bigger than the mechanical energy so it kind off takes over the mechanical energy. but if the friction decreases mechanical energy can work on the object again
Spending more time with her grandchildren is most likely a short-term goal
for a person of which of these ages?
A. 20 years old
B. 10 years old
C. 30 years old
D. 60 years old
Answer:60
Explanation:
How long will it take the cart to to travel 2.8m, starting from rest?
Answer:
0.748seconds
Explanation:
s = 1/2 *g*t^2
2.8 = 1/2 * 10* t^2
5.6 = 10 * t^2
0.56 = t^2
t = √0.56
t = 0.7483seconds
Why is the time period of a charged particle in a uniform magnetic field independent of velocity??
Answer:
time period is independent of K.E of particle, it is inversely proportional to specific charge of the particle and it is independent of angle between velocity and magnetic field
who is the father of computer but not Charles Babbage can anyone guess
Answer:
It's Obusively charles Babbage I guess
Claire rides her scooter to school, traveling 25 km/h. How much time in minutes does it take her to travel to her school, which is 4 km away ?
Answer:
9.6 minutes
Explanation:
We have that it takes Claire [tex]t=0.16h[/tex] amount of time to get to school
[tex]t=0.16h[/tex]
From the Question we are told that
Velocity[tex]v= 25 km/h.[/tex]
Distance [tex]d=4km[/tex]
Generally the equation for Time is mathematically given as
[tex]v=\frac{d}{t}\\\\t=\frac{4}{25}\\\\t=0.16h[/tex]
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(x – 2)² = 5(y + 1), where x and y are measured in centimeters. You need to place a new light bulb in your flashlight. How far away from the vertex of the parabolic mirror should you place the bulb to ensure a perfect beam of light? The bulb should be placed .
Answer:
The coordinates of the point the bulb should be placed is (2, 0.25)
Explanation:
The given equation of a parabola is presented as follows;
(x - 2)² = 5·(y + 1)
The point the bulb should be placed is the focus of the parabolic mirror to ensure a perfect (straight) beam
The general form of the equation of a parabola is (x - h)² = 4·p·(y - k)
The coordinates of the focus of the parabola for p > 0 f = (h, k + p)
By comparison, h = 2, k = -1, and p = 5/4
∴ The coordinates of the focus of the parabola, f = (2, -1 + 5/4) = (2, 0.25)
The coordinates of the point the bulb should be placed is at the focus, f = (2, 0.25).
Two tuning forks, 492 Hz and 498 Hz, are struck simultaneously. How many beats will be heard?
none
2.00 beats
4.00 beats
6.00 beats
Answer:
6 beats
If one fork beats once and another twice in the same time period
you would hear 1 beat. (Same for 2 and 3 beats).
I need help answer these questions please
Answer:
1. 25 J
2. 250 J
3. 900,000 J
4. 7,500 J
Explanation:
1. The distance the wheelbarrow is tilted, d = 0.5 m
The force used to tilt the wheelbarrow, F = 50 N
The work done, W = F × d
∴ W = 50 N × 0.5 m = 25 J
2. Work done, W = Force × Distance
The applied force, F = 50 N
The distance the sand is moved, d = 5 m
∴ W = 50 N × 5 m = 250 J
3. The work done, W = The load lifted × The height to which the load is lifted
∴ W = 90,000 N × 10 m = 900,000 J
The work done, W = 900,000 J
4. The work output of the skateboard = The work input × Efficiency
Given that the skateboard is an ideal machine, we have;
The work output of the skateboard = The work input = W
W = F × d
F = 15 N, d = 500 m
∴ W = 15 N × 500 m = 7,500 J
The work output of the skateboard = W = 7,500 J.
A room has a rectangular shape of 4000 mom by 3600mm according to the architecture plan It is supposed to be fitted with tiles which are square in shape and size of 12 cm. How many tiles are required to cover the entire floor
Explanation:
First find the area of the entire floor:
Area of a rectangle= length × width
( 4000mm× 3600mm)
14400000mm²
Area of one square tile??= side ×side
12cm×12cm
144cm²
Convert cm to mm
1cm²=100mm²
144cm²=144cm²/1cm²×100mm²
=14,400mm²
Number of tiles required to cover the entire floor= 14400000mm²/14400mm²
=1000
Eratosthenes measured the circumference of Earth to within 4% of the correct value
A. Looking at stick shadows on the equinox.
B. Noting how much more of the celestial sphere came into view when walking south.
C. Sighting the stars from within the deepest well in Egypt on the day of the solstice.
D. Using the detailed reports of far-sailing mariners
Answer:
A. Looking at stick shadows on the equinox.
Explanation:
He measures the circumference by placing a pole when the sun is overhead on the days of solstice. He determined the circumference by measuring the difference between Alexandria to Syene and the angle of the pole's shadow.
The equation used for the calculation of circumference is as follow
[tex]\frac{360 degrew}{7.2 degree} = \frac{Circumference of earth}{Distance from Alexandria to Syene}[/tex]
Please refer to the following link for more details
https://www.khanacademy.org/humanities/big-history-project/solar-system-and-earth/knowing-solar-system-earth/a/eratosthenes-of-cyrene
what is the difference between static electricity produced by friction, conduction of electricity, and induction of an electrical charge?
Answer:
ummm a whole bunch
Explanation:
pleaase help me i don't know this !!!
Answer:
coefficient=1.09N/m×g
coefficient=1.09N/0.413g×10m/s square
coefficient=1.09N/4.13N
coefficent=0.263
f= uK
here f is force, u is cofficient of friction , k is normal force
k = mg
f = umg
1.09 = u × 0.41 × 10
u = 1.09 ÷ 4.1
u = 0.26
Which has greater kinetic energy, a car traveling at 40 mph or a half-as-massive car traveling at 80 mph?
a
-The 40 mph car
-The 80 mph car
-Both have the same kinetic energy
-Neither has kinetic energy
Answer:
The 80 mph car
Because the formula says 1/2 mass but for the velocity it is squared
Please answer this question sqdancefan
Answer:
(D) 4
Explanation:
The percentage error in each of the contributors to the calculation is 1%. The maximum error in the calculation is approximately the sum of the errors of each contributor, multiplied by the number of times it is a factor in the calculation.
density = mass/volume
density = mass/(π(radius^2)(length))
So, mass and length are each a factor once, and radius is a factor twice. Then the total percentage error is approximately 1% +1% +2×1% = 4%.
_____
If you look at the maximum and minimum density, you find they are ...
{0.0611718, 0.0662668} g/(mm²·cm)
The ratio of the maximum value to the mean of these values is about 1.03998. So, the maximum is 3.998% higher than the "nominal" density.
The error is about 4%.
_____
Additional comment
If you work through the details of the math, you will see that the above-described sum of error percentages is just an approximation. If you need a more exact error estimate, it is best to work with the ranges of the numbers involved, and/or their distributions.
Using numbers with uniformly distributed errors will give different results than with normally distributed errors. When such distributions are involved, you need to carefully define what you mean by a maximum error. (By definition, normal distributions extend to infinity in both directions.) While the central limit theorem tends to apply, the actual shape of the error distribution may not be precisely normal.
Answer:
D. 4Explanation:
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justoko2
A radio has a 1.3 A current. If it has a resistance of 35 Ω, what is the potential difference?
Answer:
22
Explanation:
Answer:
45.5 v
Explanation:
I = 1.3 A
R = 35 Ω
V = I * R
V = 1.3 * 35 = 45.5 v
A ball is dropped from the top of a building. It initially
moves at 40 m/s. After 0.5 seconds, it moves at 3.8
m/s.
What force is responsible for the slowing of the ball?
air resistance
gravity
normal
tension
Answer:
Explanation:
I'm assuming you missed the decimal point in the initial velocity and that it should be 4.0 m/s. If after a half of a second it is moving a tiny bit slower, it would be because of air resistance. You can only neglect air resistance if the problems you are doing tell you neglect it.
Answer:
Air resistance
Explanation:
I got it correct on the quiz :)
A pole-vaulter first converts kinetic energy into
a. thermal energy.
b. chemical energy. mechanical energy.
c. mechanical energy
d. elastic potential energy.
Answer:
d. elastic potential energy
Questlon 20 of 20 Which change to an object would quadruple its kinetic energy?
A. Reducing its mass to one-half of its original value
B. Increasing its velocitato twice its original value
C. Reducing its velocity to one-half of its original value O
D. Increasing its mass to twice its original value
Answer:Whenever the velocity of the object increases or usually doubles, the kinetic energy will be quadrupled. If in case you are not familiar with kinetic energy, this is known as the type of energy that is in motion. The greater the mass of the object, the greater the total of the energy
Explanation:
Change to an object would quadruple its kinetic energy Increasing its velocity to twice its original value
What is kinetic energy?
In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. The same amount of work is done by the body when decelerating from its current speed to a state of rest. Formally, kinetic energy is any term in a system's Lagrangian which includes a derivative concerning time.
In classical mechanics, the kinetic energy of a non-rotating object of mass m traveling at a speed v is [tex]{\textstyle {\frac {1}{2}}mv^{2}}[/tex]
In relativistic mechanics, this is a good approximation only when v is much less than the speed of light.
The standard unit of kinetic energy is the joule, while the English unit of kinetic energy is the foot-pound.
Learn more about kinetic energy
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PLEASEE HELPP!!!
Describe melting.
Describe evaporation.
Describe boiling.
Describe condensation.
Describe freezing.
Melting: the substance changes back from the solid to the liquid
Evaporation: the process by which water changed from a liquid to a gas.
Boiling: the process by which a liquid turns into a vapor when it is heated to it's boiling point.
Condensation: the substance changed from a gas to a liquid
Freezing: the substance changed from a liquid to solid.
Answer:
Melting is a process that causes a substance to change from a solid to a liquid.
Evaporation is the process of turning from liquid into vapour.
Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the
Condensation is the process of water vapor turning back into liquid water
Freezing is a phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point
The drone can fly for 25 minutes before the battery needs recharging.
The power output of the battery is 65.0 W
Calculate the maximum energy stored by the battery.
Answer:
105.6 KJ
Answer
3.7/5
4
hope this will help you friend.
A football is projected at an angle of 30 from the ground with a n initial velocity of 10 m/s, take acceleration due to gravity is g= 10m/s2 .what is the time of flight
Answer: i dont know
Explanation:
Answer:
[tex]{ \bf \: time \: of \: flight : s = 0} \\ { \tt \: s \: is \: displacement} \\ \\ s = ut + \frac{1}{2} a {t}^{2} \\ 0 = u \sin( \theta) t - \frac{1}{2} g {t}^{2} \\ u \sin( \theta)t = \frac{1}{2} g {t}^{2} \\2 u \sin( \theta) = gt \\ { \boxed{ \tt{formular : time \: of \: flight = \frac{2u \sin( \theta) }{g} }}} \\ t = \frac{2 \times 10 \times \sin(30 \degree) }{10} \\ { \green{ \boxed{ \tt{ \bf{answer : { \tt{time \: of \: flight =1 \: second }}}}}}} \\ \\ { \tt{becker \: jnr}}[/tex]
Two uniform bars of the same dimensions are constructed from the same material. One bar has five evenly spaced holes through it and the second bar has only two holes. In these cases, the bars are slid over vertical pegs and rest on a horizontal surface, where friction between the bar and the surface is negligible. The two bars are each pulled by
horizontal forces of equal magnitude F from their right end as shown above. The bars' resulting angular accelerations are recorded.
Is the magnitude of the initial angular acceleration of the bar in case 1 larger than, smaller than or equal to the magnitude of the initial angular acceleration of the bar in Case 2? Explain your reasoning.
Solution :
The angular acceleration, [tex]$\alpha$[/tex] is obtained from the equation of the [tex]$\text{Newton's second law}$[/tex] of rotational motion,
Thus,
[tex]$\tau = F \times d$[/tex]
or [tex]$\tau = I \times \alpha$[/tex]
where [tex]$\tau$[/tex] is torque, F is force, d is moment arm distance, I is the moment of inertia
Thus, [tex]$\alpha=\frac{(F\times d)}{I}$[/tex]
Now if the force and the moment arm distance are constant, then the [tex]\text{angular acceleration is inversely proportional to the moment of inertia.}[/tex]
That is when, F = d = constant, then [tex]$\alpha \propto \frac{1}{I}$[/tex] .
Thus, moment of inertia, I is proportional to mass of the bar.
The mass is less for the bar in case (1) in comparison with that with the bar in case (2) due to the holes that is made in the bar.
Therefore, the bar in case (1), has less moment of inertia and a greater angular acceleration.
when is the acceleration of body is positive negative and zero?
Answer:
【 In vector form , if angle between velocity vector and acceleration vector is less than 90° and greater than 0° then it is positive acceleration and if it is less than 180° and greater than 90° then it is negative acceleration. If there is no acceleration vector then it is called zero acceleration. 】
A constant unbalanced force is applied to an object for a period of time. What will happen to the objects acceleration?
a. It will accelerate in the direction of the net force.
b. It will accelerate opposite the direction net force.
c. There is no acceleration.
d. Not enough information to answer
Answer:
A
Explanation:
The moving object will accelerate as long as a net force is applied. If a net force is not applied, the object will continue to move at a constant speed along the same path in curved spacetime (due to gravity). If the net force continues the velocity of the object will continue to increase until nearly reaching the limit (speed of light).
