Answer:
True
Explanation:
If an object is at rest it will stay at rest unless a force acts on it.
A pendulum Bob released from some initial height such that the speed of the bob at the bottom of the swing is 1.9m/s. What is the initial height of the bob?
Answer:
h = 18.4 cm
Explanation:
Given that,
The speed of the bob at the bottom of the swing is 1.9m/s.
We need to find the initial height of the bob. Let it is h.
We can find it using the conservation of energy i.e.
[tex]mgh=\dfrac{1}{2}mv^2[/tex]
Where
v is speed of the bob
So,
[tex]h=\dfrac{v^2}{2g}\\\\h=\dfrac{(1.9)^2}{2\times 9.8}\\\\h= 0.184\ m[/tex]
or
h = 18.4 cm
So, the initial height of the bob is 18.4 cm.
The initial height of bob will be "18.4 cm".
Speed and height:Speed would be the scalar quantity that describes "how quickly an attribute moves." This could sometimes be defined as this same rate whereby an object travels a given distance.
According to the question,
The speed of the bob = 1.9 m/s
Let,
The initial height be "h".
By using the conservation of energy, we get
→ mgh = [tex]\frac{1}{2}[/tex]mv²
or,
→ h = [tex]\frac{v^2}{2g}[/tex]
By substituting the values, we get
= [tex]\frac{(1.9)^2}{2\times 9.8}[/tex]
= 0.184 m or,
= 18.4 cm
Thus the above answer is correct.
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I need help with this, I can't figure it out.
Here is the link:
https://platform.breakoutedu.com/game/play/fun-in-the-sun-140559-XMWCQF1LPL
Answer:
Star, Triangle, Circle, Rhombus, Square.Left, Down, Right, Down, Up.2,3,2,4.L,O,O,K,I,N,G,F,L,Y.Explanation: You're welcome ✓
Could a sea breeze occur at night? Explain why or why not.
ELE Review questions
POSSIBLE POINTS: 3
Match the energy transformation sequence with the device it describes:
A hair dryer plugged into the wall
a
A hand crank generator emergency radio
A battery operated fan
11 CE to ELE
+ ELE to KE
:: KE to ELE
h
1
2
A Review
Answer:
1. ELE to KE = Electrical energy conversion to kinetic energy.
2. KE to ELE = kinetic energy conversion to electrical energy.
3. CE to ELE = chemical energy conversion to electrical energy.
Explanation:
The Law of Conservation of Energy states that energy cannot be destroyed but can only be transformed or converted from one form to another.
Some examples of energy are chemical energy, electrical energy, kinetic energy, sound energy, potential energy, light energy, etc.
The transformation of energy from one form to another are described below;
1. A hair dryer plugged into the wall: it involves the conversion of electrical energy to kinetic energy. The energy type present in the wall socket is electrical energy which powers the hair dryer to have kinetic energy i.e the energy possessed due to motion of hair dryer.
2. A hand crank generator emergency radio: it illustrates the conversion of kinetic energy to electrical energy. The hand crank generator possess kinetic energy as it is being wounded before it is then converted into electrical energy which powers the radio.
3. A battery operated fan: it illustrates the conversion of chemical energy to electrical energy. The cells present in battery possess chemical energy that is being converted into electrical energy to power the fan.
Select all the correct locations on the image.
Which hot spots identify features in the image that can help lower the effects of urbanization?
Answer:
its the top 3 can confirm on plato
Explanation:
Answer:
plato
Explanation:
A copper wire of length L and cross-sectional area A has resistance R. A second copper wire at the same temperature has a length of 2L and a cross-sectional area of A. What is the resistance of the second copper wire?
A. 2R
B. 4R
C. R
D. 1/2 R
Answer: 4R
Explanation:R=pL/A
R second wire=p2L/1/2A
=4R
A spacecraft drifts through space at a constant velocity. Suddenly, a gas leak in the side of the spacecraft gives it a constant acceleration in a direction perpendicular to the initial velocity. The orientation of the spacecraft does not change, so the acceleration remains perpendicular to the original direction of the velocity. What is the shape of the path followed by the spacecraft in this situation
Answer: The path will be a parabola.
Explanation: The path is a parabola because the motion described is a projectile motion, in which an object thrown or projected is subjected only to the acceleration.
In this motion, velocity must be constant and horizontal and acceleration is perpendicular compared to the direction of the velocity. In these conditions, the path is a parabola and the motion is a projectile.
Which factors affect the gravitational force between two objects?
-
distance and velocity
O mass and distance
O mass and weight
acceleration and weight
TELE
Answer:
mass and distance
Explanation:
mass, and distance. The force of gravity depends directly upon the masses of the two objects, and inversely on the square of the distance between them.
A capacitor and an electric source are both connected to a light bulb. If the power source is momentarily disconnected from the circuit, what will happen to the light bulb?
Group of answer choices
It will get brighter because the capacitor is providing more power than the electrical source.
It will no light because the electric source is the only thing required to power the bulb.
It will stay momentarily lit because the capacitor is supplying a voltage.
It will flash on and off because of the unstable power.
Answer:
It will no light because the electric source is the only thing required to power the bulb.
Explanation:
A 20.0 newton force is used to push a 2.00 kilogram cart a distance of 5.00 meters how much work is done on the cart
Answer:
100
w=f*s
20*5=100....
100 Joules of work is done on the cart.
What is Work done?Work done by a force is defined as the product of the displacement and the component of the applied force on the object in the direction of displacement. When we push a block with some force, the body moves with some acceleration, so it is called work done.
Work done is expressed as W=Fd and its unit is joules which can be defined as the amount of work done by a force in Newton is applied to an object, as a result of which it is displaced in meter.
For above given information,
Force= 20 N
Distance= 5 m
So, work done= 20*5= 100 Joules
Thus, 100 Joules of work is done on the cart.
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A Drive to the BeachMary drove from her home to the beach that is 30 mi from her house. The first 15 mi she drove at 60 mph, and the next 15 mi she drove at 30 mph. Would the trip take more, less, or the same time if she traveled the entire 30 mi at a steady 45 mph
Answer:
Explanation:
Let us calculate the average velocity .
Average velocity = total distance / total time
Time taken to drive first 15 mi
= 15 / 60 = .25 h
Time taken to drive next 15 mi
= 15 / 30 = .5 h
Total time = .25 + .5 = .75 h
Total distance = 30 mi
average speed = 30 / .75
= 40 mi / h
So average speed is 40 mph which is less than given velocity of 45 mph .
Hence if she travels at 45 mph , she will take less time .
se the following graph describing a motorcycle's motion to answer the question below.
if a=8i+j-2k and b=5i-3j+k what is the value of b X a
Distribute the product:
a×b = (8i + j - 2k) × (5i - 3j + k)
a×b = 8i × (5i - 3j + k) + j × (5i - 3j + k) - 2k × (5i - 3j + k)
a×b = (40 (i×i) - 24 (i×j) + 8 (i×k))
… … … + (5 (j×i) - 3 (j×j) + k×j)
… … … + (-10 (k×i) + 6 (k×j) - 2 (k×k))
Recall the definition of the cross product:
i×i = j×j = k×k = 0 (the zero vector)
i×j = k
j×k = i
k×i = j
and for any two vectors x and y, we have x×y = -(y×x).
So we have some cancellation and rewriting:
a×b = (40 (i×i) - 24 (i×j) + 8 (i×k))
… … … + (5 (j×i) - 3 (j×j) + j×k)
… … … + (-10 (k×i) + 6 (k×j) - 2 (k×k))
a×b = (-24k - 8j) + (-5k + i) + (-10j - 6i)
a×b = -5i - 18j - 29k
Then
b×a = -(a×b) = 5i + 18j + 29k
A cube of wood with a side length of 1 meter is place in the water. It half of the wood sank under the water, find the mass of the wood. (density of water 1.0 × 103kg/m3)
Answer:
Volume of cube is equal to two times the weight of replaced water [tex]1000[/tex] Kg
Explanation:
Length of one side of cube is [tex]1[/tex] meter
Volume of cube [tex]= 1* 1* 1 = 1[/tex] cubic meter
Half of the wood sank
Hence, the volume of water replaced will be equal to half the volume of cube
Volume of water replaced [tex]= \frac{1}{2} = 0.5[/tex] cubic meter
Density of water [tex]1 * 10^3[/tex] kg/m3
Weight of water replaced
[tex]= 1 * 10^3 * 0.5\\= 500[/tex]Kg
Volume of cube is equal to two times the weight of replaced water
[tex]= 2* 500 = 1000[/tex] Kg
Calculate the amount of potential difference in a capacitor of 0.9 MF , If the amount of charge is 1.4x10^-4 C .(Show all the work)
Answer:
Potential difference [tex]V=1.6\times 10^{-10}\ V[/tex]
Explanation:
Capacitance of capacitor, C = 0.9 MF
Charge, [tex]Q=1.4\times 10^{-4}\ C[/tex]
We need to find the amount of potential difference. We know that,
[tex]Q=CV[/tex]
V is potential difference
So,
[tex]V=\dfrac{Q}{C}\\\\V=\dfrac{1.4\times 10^{-4}}{0.9\times 10^6}\\\\V=1.6\times 10^{-10}\ V[/tex]
So, the required potential difference is [tex]1.6\times 10^{-10}\ V[/tex].
Friction produces heat because it causes molecules to move faster and
have more energy.
True or false.
Answer:
True
Explanation:
Friction occurs because no surface is perfectly smooth. Even surfaces that look smooth to the unaided eye make look rough or bumpy when viewed under a microscope. You know that friction produces heat. That’s why rubbing your hands together makes them warmer. But do you know why? Friction causes the molecules on rubbing surfaces to move faster, so they have more energy. This gives them a higher temperature, and they feel warmer. Heat from friction can be useful. It not only warms your hands.
Review. As it passes over Grand Bahama Island, the eye of a hurricane is moving in a direction 60.08 north of west with a speed of 41.0 km/h. (a) What is the unit-vector expression for the velocity of the hurricane
Answer:
Velocity = -20.45 i + 35.54 j km/h
Explanation:
given data
speed v = 41.0 km/h
direction = 60.08 north of west
solution
first we get here Speed in west direction that is express as
Speed in west direction = v × cos(60.08) ..........................1
Speed in west direction = 41 × cos(60.08)
Speed in west direction = 20.45 km/h
now we get Speed in north direction that is
Speed in north direction = v × sin(60.08) ............................2
Speed in north direction = 41 × sin(60.08)
Speed in north direction = 35.54 km/h
so Velocity will be here
Velocity = -20.45 i + 35.54 j km/h
Observer A, who is at rest in the laboratory, is studing a particle that is moving through the laboratory at a speed of 0.624c and determines its lifetime to be 159ns a) Obsever A places markers in the laboratory at the locations where the particle is produced and where it decays. How far apart are those markers in the laboratory? b) Obsever B, who observes the particle to be at rest and measures its lifetime to be 124ns. According to B, how far apart are the two markers in the laboratory?
Answer:
a) the markers are 29.76 m far apart in the laboratory
b) According to B, the markers are 23.21 m far apart in the laboratory
Explanation:
Given that;
speed of particle = 0.624c = (0.624 × 3×10⁸m/s)
{ where c is the speed of light}
lifetime of the particle t = 159ns = 1.59 × 10⁻⁷
a) Observer A places markers in the laboratory at the locations where the particle is produced and where it decays. How far apart are those markers in the laboratory
lets apply the formula distance = velocity × time
lets substitute
distance = (0.624×3×10⁸ m/s) × (1.59 × 10⁻⁷ s)
distance = 29.76 m
Therefore, the markers are 29.76 m far apart in the laboratory
b) Observer B, who observes the particle to be at rest and measures its lifetime to be 124ns. According to B, how far apart are the two markers in the laboratory?
lifetime of the particle t = 124ns = 1.24 × 10⁻⁷
distance = (0.624×3×10⁸ m/s) × (1.24 × 10⁻⁷ s)
distance = 23.21 m
Therefore, According to B, the markers are 23.21 m far apart in the laboratory
A physicist attempts to use Newton's laws of motion to predict the behavior of a molecule of water, but the laws fail to give accurate predictions. What is the most likely reason?
A) Liquids do not follow the laws of motion.
B) The molecule is small enough so that quantum effects are important.
C) Newton’s laws apply to atoms, but not to molecules.
D) The molecule was likely traveling at a near-light speed.
Answer:
B) The molecule is small enough so that quantum effects are important.
Explanation:
The molecules of water behave like wave and their motion cannot be accurately predicted by classical physics laws but can be properly predicted by quantum theory.
Classical physics describes matter that behave like solid particles while quantum effect describes matter that behaves like waves.
Therefore, the correct option is B.
What happens to ar object in free fall?
Suppose a meteor of mass 2.50 x 1013 kg is moving at 33.0 km/s relative to the center of the Earth and strikes the Earth. Suppose the meteor creates the maximum possible decrease in the angular speed of the Earth by moving toward the west and striking a point on the equator tangentially. What is the change in the angular speed of the Earth due to this collision
Answer:
change is imperceptible
w_f = 7.272 10⁻⁵ rad / s
Explanation:
For this exercise we can use the conservation of angular momentum.
Initial. Before the crash
L₀ = I w₀
final. After the crash
L_f = I w_f + p r
where the moment is
p = mv
As the system is formed by the two bodies, the forces during the impact are internal, therefore the angular momentum is conserved
L₀ = L_f
I w₀ = I w_f + m v r
w_f = w₀ - [tex]m \frac{ v \ r }{I}[/tex]
We can approximate the Earth to a sphere, so its angular momentum is
I = 2/5 M r²
we substitute
w_f = w₀ - [tex]\frac{5 \ m \ v}{2 \ M \ r}[/tex]
We can find the angular velocity of the Earth with the duration of a spin which is the period of one day
w₀ = 2π / T
T = 24 h (3600 s / 1h) = 86 400 s
w₀ = 2π / 86400
w₀ = 7.272 10⁻⁵ rad / s
let's calculate
w_f = 7.27 10⁻⁵ - [tex]\frac{5 \ 250 \ 10^{13} \ 33.0 \ 10^{3} }{ 2 \ 5.98 \ 10^{24} \ 6.37 10^{6} }[/tex]
w_f = 7.272 10⁻⁵ - 1.0829 10⁻¹³
w_f = 7.27199999 10⁻⁵
this change is imperceptible
w_f = 7.272 10⁻⁵ rad / s
Sound will travel fastest in air at _____.
-5°C
0°C
10°C
15°C
The following table lists the speed of sound in various materials. Use this table to answer the question.
Substance
Speed (m/s)
Glass
5,200
Aluminum
5,100
Iron
4,500
Copper
3,500
Salt water
1,530
Fresh water
1,500
Mercury
1,400
Hydrogen at 0°C
1,284
Ethyl Alcohol
1,125
Helium at 0°C
965
Air at 100°C
387
Air at 0°C
331
Oxygen at 0°C
316
Answer:
iron/copper
iron faster because it in the core so iron is the answer with would be 15C because its the hottest in the core and is very quick there to being moved by the core so iron being 15C is the answer.
Explanation:
Convert the arc length of 6.86 radians into cycles.
Plz convert this for me people have been putting random comments
Answer:
1.092 cycles
Explanation:
We need to convert the arc length of 6.86 radians into cycles.
We know that,
1 radian = 0.1592 cycles
To convert 6.86 radians to cycles, we use unitary method.
6.86 radian = (0.1592 × 6.86) cycles
= 1.092 cycles
Hence, there are 1.092 cycles in 6.86 radians. Hence, this is the required solution.
Question 6
2 pts
Jenny loves puffed rice cereal. As she is pouring the cereal, two little pieces of cereal each with
equal charges of 1.85 x10-18 coulombs fall into the bowl 0.025 meters apart. Use Coulomb's Law
to find the electrostatic force between them. (Remember, Coulomb's constant is 8.99 x10
N*m²/C2)
4.9 x 10-23 N
6.2 x 10-15 N
9.0 x 10-3N
2.5 x 10-23 N
Answer:
4.9 x 10-23 N
Explanation:
I took the test
Convert the arc length of 3.05 degrees into meters.
That depends on the circle's radius, which you neglected to mention.
If the radius is 1 meter, then an arc of 3.05 degrees is 5.32 centimeters long.
If the radius is 1 kilometer, then an arc of 3.05 degrees is 53.2 meters long.
a water tank holds water to the depth of the 80cm what is the pressure of the water of the tank
Answer:
7976 Pascals significant figure= 7.9*10^3
Explanation:
formula of hpg = height*density*gravitational energy
.80*10*997=7976 pascals
The specific heat of water is 4,186 J/kg.'C. Approximately how much heat must
be removed from 0.500 kg of water to change its temperature from 24.0°C to
5.00°C?
Explanation:
Q= mc∆T
∆T= 5-24=- 19
Q= 0.5*4186*-19
Q= -39767 J
negative sign show heat releases
A volleyball player spiking is it kinetic or potential
Answer:
It is kinetic energy.
Explanation:
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 the volleyball from rest to its stated velocity. Having gained this energy from the player spiking it during its acceleration, the body maintains this kinetic energy unless its speed changes.
A stone is dropped off of a 123 meter cliff and falls to the ground below. How long does it take for the stone to hit the ground
25.10 or 24.6m/s both answers are correct
Explanation:
firstly , divide the multiply with 2 and divide the result by acceleration due to gravity which is 9.8m/s or 10m/s
123*2=246
246/9.8 or 10
= 25.10 or 24.6m/s
What attitudes and actions can group leaders take in trying to establish trust within a group during the initial stage of group development? How is each attitude and action important in the process of initiating trust?
Answer:
i dont know!
Explanation: