Answer:
A. It pulls objects towards the center of Earth.
Explanation:
Think about dropping something, where does it go? If you are on earth, this goes down towards the ground due to the attractive force of gravity on every object (to pull everything to center of earth). Like Newton's apple.
8. What force is needed to accelerate an elevator upward at a rate of 2m's if the mass of the
elevator is 2,350kg
Answer:
F = M a
F = 2350 kg * 2 m/s^2 = 4700 Newtons
That is in addition to the force of
F = 2350 * 9.8 m/s^2 = 23,030 N needed for a stopped elevator
If the scientific method was not used in forensic science at all, what do you think some potential problems could be?
what temperature change is required to change the length of a 5.5-m steel beam by 0.0012m?
Answer:
Length of steel = 5.5 m
Increase in length = 0.0012 m
α of steel = 12 x 10-6/K
To find:
Temperature change needed ?
Calculation:
Let the required temperature change be ∆T. (in the photo)
So, temperature change of 18.1 Kelvin is required
I hope I have helped you and go to my profile to help me with my question, I really need It, thanks.
The half-life of radium-226 is 1,600 years and the half-life of carbon-14 is 5,730 years. in one to two sentences, mathematically prove that the decay constant for radium-226 is larger than the decay constant for carbon-14.
please and thank you :)
Explanation:
-226 of 1600
-14 of 5730
-226×16÷100= -36.16
-14×57.3÷100= -802.2
The decay constant for radium-226 is larger than the decay constant for carbon-14.
What is decay constant?Decay constant of radioactive substance is its probability of decay per unit time.
Decay constant for radium-226 is [tex]1.4*10^{-11} /sec[/tex] and for carbon-14 is [tex]3.8*10^{-12} /sec[/tex].
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When a person sees something, what carries the message from the eyes to the brain?
Answer:
nerves
Explanation:
The optic nerve is the nerve in each eye that carries the signal from your eye to your brain.
The diagram shows a roller-coaster track. Assume that the system is closed. At point D, the roller-coaster is upside-down and at the top of the vertical loop.
which statement best describes the potential and kinetic energies of a roller-coaster car at point D?
Any sound with a frequency that is too low for humans to hear is called:
Answer:
infrasound
Explanation:
Select the correct location on the image.
Answer:
Violet (Shortest Wave Length)
Explanation:
Violet waves have the highest frequencies. The highest frequencies have the shortest wave length.
The sun will spend most of its lifetime in which stage?.
A 5.0-kg block is pulled horizontally across a floor by a string attached to it with an acceleration of 2 m/s2. What is the tension in the string if the coefficient of sliding kinetic friction between the block and floor is 0.2
The tension on the string when the coefficient of sliding kinetic friction between the block and floor is 0.2 is calculated as 19.8N
What is the tension on the string?The force acting on the block in the horizontal direction is given by:
F_net = ma
where F_net is the net force acting on the block, m is the mass of the block, and a is its acceleration.
The force of friction opposing the motion of the block is given by:
F(friction) = μKN
where μK is the coefficient of kinetic friction between the block and the floor, and N is the normal force acting on the block due to the floor.
Since the block is pulled horizontally, the normal force acting on the block is equal and opposite to the weight of the block, which is given by:
N = mg
where g is the acceleration due to gravity.
Therefore, the net force acting on the block is:
Fnet = T - F (friction) = ma
where T is the tension in the string.
Substituting the expressions for F (friction), N, and Fnet, we get:
T - μKmg = ma
Solving for T, we get:
T = ma + μKmg
Substituting the given values, we get:
T = (5.0 kg)(2 m/s^2) + (0.2)(5.0 kg)(9.8 m/s^2)
Simplifying, we get:
T ≈ 19.8 N
Therefore, the tension in the string is approximately 19.8 N.
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An automobile moves on a level horizontal road in a circle of radius 40.0 m. The coefficient of friction between tires and road is 0.60. The maximum speed with which this car can round this curve is
Answer:
Approximately [tex]15\; {\rm m\cdot s^{-1}}[/tex] (assuming that [tex]g = 9.81\; {\rm m\cdot s^{-2}}[/tex].)
Explanation:
Let [tex]m[/tex] denote the mass of this vehicle, and let [tex]g[/tex] denote the gravitational field strength.
Since the road is level, the normal force that the road exerts on the vehicle would be equal in magnitude to the weight [tex]m\, g[/tex] of this vehicle. That is: [tex]F_\text{normal} = m\, g[/tex].
Let [tex]\mu_{k}[/tex] denote the coefficient of (kinetic) friction between the tires of this vehicle and the road. The maximum friction that the road could exert on this vehicle would be:
[tex]\begin{aligned}& F_\text{max. friction} && (\text{max. friction}) \\ =\; &\mu_{k}\, F_\text{normal} && (\text{coefficient of friction}) \,(\text{normal force}) \\ =\; & \mu_{k}\, m\, g\, \end{aligned}[/tex].
Also because this road is level, the only unbalanced force on this vehicle would be friction. Thus, the net force on this vehicle would be equal to the friction that the road exerts on the vehicle, which is at most [tex]\mu_{k}\, m\, g[/tex]:
[tex]\begin{aligned}& F_\text{net} && (\text{net force}) \\ =\; & F_\text{friction} && (\text{friction}) \\ \le \; & F_\text{max. friction} && (\text{max. friction})&\\ =\; & \mu_{k}\, m\, g\, \end{aligned}[/tex].
In other words, [tex]F_\text{net} < \mu_{k}\, m\, g[/tex]. This inequality could provide an upper bound on the acceleration of this vehicle:
[tex]\begin{aligned}& a && (\text{acceleration}) \\ =\; & \frac{F_\text{net}}{m} && \genfrac{}{}{0em}{}{(\text{net force})}{(\text{mass})}\\ \le \; & \frac{\mu_{k}\, m\, g}{m} \\ =\; & \mu_{k}\, g\end{aligned}[/tex].
Thus, the maximum acceleration of this vehicle on this road would be [tex]a_\text{max} = \mu_{k}\, g[/tex].
Let [tex]r[/tex] denote the radius of this circle. When the vehicle is moving around this circle at a speed of [tex]v[/tex], the (centripetal) acceleration of this vehicle would continuously be [tex]a = (v^{2} / r)[/tex].
Since the upper bound of the acceleration of this vehicle is [tex]a_\text{max} = \mu_{k}\, g[/tex], rearrange the equation [tex]a = (v^{2} / r)[/tex] to find an upper bound on speed [tex]v[/tex]:
[tex]\begin{aligned}\frac{v^{2}}{r} &= a \\ & \le a_{\text{max}} \\ &= \mu_{k}\, g\end{aligned}[/tex].
[tex]v^{2} \le \mu_{k}\, g\, r[/tex].
[tex]v \le \sqrt{\mu_{k}\, g\, r}[/tex].
In other words, when the radius of the circle is [tex]r[/tex], the coefficient of friction between the tire and the ground is [tex]\mu_{k}[/tex], and the gravitational field strength is [tex]g[/tex], the maximum speed of the vehicle would be [tex]\sqrt{\mu_{k}\, g \, r}[/tex].
In this question, it is given that [tex]r = 40.0\; {\rm m}[/tex] whereas [tex]\mu_{k} = 0.60[/tex]. Assuming that [tex]g = 9.81\; {\rm m\cdot s^{-2}}[/tex], the maximum speed of this vehicle would be:
[tex]\begin{aligned}v_\text{max} &= \sqrt{\mu_{k}\, g\, r} \\ &= \sqrt{0.60 \times 9.81\; {\rm m\cdot s^{-2}} \times 40.0\; {\rm m}} \\ &\approx 15\; {\rm m\cdot s^{-1}}\end{aligned}[/tex].
If the half-life of iodine-131 is 8.10 days, how long will it take a 50.00 g sample to decay to 6.25 g?
The time it will take to decay 6.25 grams is 24.4684 days.
What is Half life period?A radioactive substance's half-life is often described as the amount of time it takes for one of its atoms to break apart or transform into another. Ernest Rutherford originally examined the theory in 1907. This is typically represented by the sign Ug or t1/2.
To make the concept clearer, let's use a radioactive element with an hour-long half-life.
Now according to the question the given values are :
T(1/2) for iodine-131 is 5.10 days,
[A]₀ for iodine-131 is 50 grams and,
[A] for iodine-131 is 6.25 grams.
T(1/2)=0.693/k
⇒8.10=0.693/k
⇒k=0.865 [tex]days^{-1}[/tex].
2.303 log [A]₀/[A]= kt
2.303 log(50.00/6.25)= 0.085×t
⇒t=1/0.085×2.303×log8
t=24.4684 days
Hence, the time it will take to decay is 24.4684 days.
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We observe the wheels of buses and trucks are heavier than the wheels of cars and scooters why.
Answer:
they carry a heavier load
Explanation:
Answer:
The wheels of buses and trucks are heavier than the wheels of car or scooters because the buses and trucks are heavy and require to exert less pressure. We know that when pressure decreases an area of contact increases, so the tires are broadened so that they exert less pressure on the road and move easily.
Explanation:
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Select the statements that apply in order to complete the model (you can choose multiple answers).
a) the products must equal the reactants.
b) one diatomic oxygen should be removed from the reactant side.
c) one unbonded carbon atom should be added to the product side of the equation.
d) one carbon atom and two oxygen atoms are needed to balance the equation.
e) one carbon dioxide molecule should be added to the product side of the equation.
The statement a,d and e are correct. The chemical equation must be balanced.
What is a chemical reaction ?One or more compounds, known as reactants, are transformed into one or more distinct substances, known as products. Such a process is known as a chemical reaction.
The given equation is;
[tex]\rm CH_4+2O_2 \arrow \rightarrow CO_2+2H_2O[/tex]
The statements that apply in order to complete the model is;
a) The products must equal the reactants.
d) One carbon atom and two oxygen atoms are needed to balance the equation.
e) One carbon dioxide molecule should be added to the product side of the equation.
Hence, statement a,d and e are correct.
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How energy efficiency can reduce energy consumption?
Answer:
The energy efficiency represents the things you can do with some amount of energy, and if you can do more with less, than it reduces the energy consumption.
Explanation:
The answer to this question is actually very simple. Imagine that you use only the half of the energy you produce, an efficiency of 50%. Lets say you need 5kJ, so you would need to produce 10kJ, because you can consume only the half. Now, imagine you increase the efficiency, you use exactly what you can generate, (efficiency of 100%). In this case, if you needed only 5kJ you would need to generate only 5kJ.
Aluminum is often melted down for recycling purposes. Assuming 1 kg of aluminum is at room temperature, what is the minimum amount of heat needed to melt it to a liquid? The specific heat capacity of aluminum is 899 J/kg°C, the melting point is 660°C, and the latent heat of fusion is 3.97 x 105 J/kg.
60 points
The minimum amount of heat needed to melt it to a liquid will be 569.067 kJ.
What is enthalpy of fusion?The minimum amount of heat needed to melt it to a liquid is known as the enthalpy of fusion.
The formula for the enthalpy of the fusion is;
[tex]\rm L_f=Q/m \\\\ L_f=mCdt/m \\\\ L_f= Cdt \\\\ L_f= 899 J/kg^0C \times (660^0-27^0) \\\\ L_f= 569,067 \ J \\\\\ L_f=569.067 \ kJ[/tex]
Hence, the minimum amount of heat needed to melt it to a liquid will be 569.067 kJ.
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Calculate the power if work is 9000 joules and time is 60 seconds
Answer:
150w
Explanation:
power = workdone/time
9000/60
150w
#2. If we have a 9V battery connected to a 100 resistor , what is the current ?
Answer:
90 mAmps
Explanation:
V=IR
V/R = I
9 v / 100 ohm = .09 amps = 90 mAmps
Why is calcium chloride an ionic bond
Answer:
lonic compounds generally form between elements that are metals and elements that are nonmetals. For example, the metal calcium (Ca) and the nonmetal chlorine (Cl) form the ionic compound calcium chloride (CaCl2). In this compound, there are two negative chloride ions for each positive calcium ion.
Explanation:
Answer:Ionic compounds generally form between elements that are metals and elements that are nonmetals. For example, the metal calcium (Ca) and the nonmetal chlorine (Cl) form the ionic compound calcium chloride (CaCl2). In this compound, there are two negative chloride ions for each positive calcium ion.
Explanation:
How would a parachute fall on the surface of the moon ? Describe. The mass of the Jupiter is
[tex]19 \times 10 ^{27} kg[/tex]
and that of the sun is
[tex]2 \times 10 ^{30} kg[/tex]
If the gravitational force acting between them is
[tex]4.166 \times 10 ^{23} newton[/tex]
calculate the distance between their centres.
Explanation:
the answer is 2.46 × 10^12
A nearsighted eye has a far point of 100 cm. Objects further than 100 cm are not seen clearly. A diverging lens is used to permit clear vision of an object placed at infinity. Find the focal length of the lens.
A diverging lens is used to permit clear vision of an object placed at infinity. The focal length of the lens is -100 cm.
What is focal length?The focal length is half of the radius of curvature of the focal lens.
By the lens maker formula,
1/f = 1/v +1/u
where, v is the image distance and u is the object distance.
Give, the object is at infinity and the image must form at 100 cm, the the focal length will be
1/f = 1/ -100 + 1/∞
f = -100 cm
The focal length must be -100 cm for the diverging lens.
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In Alberta, which of the following statements is true?
A. Only adults must be restrained in a vehicle.
B.All children must have booster seats.
C.Babies must be restrained in the front seat only.
D.All occupants must be restrained in a vehicle.
The half-life of Calcium-47 is 3.91 x 105 seconds. A sample contains 4.11 x 1076 nuclei. How much of the sample is left after 7.82 x 10 seconds?
2.57 x 1015 nuclei
5.14 x 1015 nuclei
1.03 x 1016 nuclei
2.06 x 1016 nuclei
Remember the formula
[tex]\\ \rm\Rrightarrow A(t)=A_o(0.5)^{\frac{t}{h}}[/tex]
h is half life[tex]\\ \rm\Rrightarrow A(7.82\times 10)=A(78.2)[/tex]
[tex]\\ \rm\Rrightarrow 4.11\times 10^{76}(0.5)^{\frac{78.2}{3.91\times 10^{5}}}[/tex]
[tex]\\ \rm\Rrightarrow 4.11\times 10^{76}(0.5)^{20\times 10^{-5}}[/tex]
[tex]\\ \rm\Rrightarrow 4.11\times 10^{76}(0.5)^{0.0002}[/tex]
[tex]\\ \rm\Rrightarrow 4.11\times 10^{76}(0.998)[/tex]
[tex]\\ \rm\Rrightarrow 4.10178\times 10^{76}[/tex]
Why no options matched?
That time given in end i.e 7.82×10
10 should contain some power to match our options .The number of nuclei of calcium-47 left after 7.82 x 10⁵s is 1.03 x 10¹⁶.
This can be found out using half life and laws of radioactive disintegration.
What are the laws of radioactive disintegration?
The Law of radioactive disintegration states the number of radioactive decay per unit time is proportional to the number of nuclei present in the sample initially.
So, ΔN/Δt = λN
Where, ΔN = number of radioactive nuclei decayed
Δt = time taken for decay
N = No of nuclei present initially
λ= decay constant
What is Half life?Half life is the time taken for the radioactive nuclei to reach half of its initial value.
Half life is given by
[tex]t_{1/2}[/tex] = λ/t
Given here, [tex]t_{1/2}[/tex] = 3/91 x 10.⁵s
N = 4.11 x 10¹⁶.
t = 7.82 x 10.⁵s
We see here that t = 2([tex]t_{1/2}[/tex])
Now, number of radioactive nuclei left undecayed in one half life is N/2
So number of nuclei left undecayed in 2 half lives will be 1/2(N/2) = N/4
So number of nuclei left in the sample will be N/4 = (4.11 x 10¹⁶.)/4
So Number of nuclei left in the sample = 1.03 x 10¹⁶.
Hence 1.03 x 10¹⁶is the correct answer.
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NAME:
A room has a 60 Watt, a 100 Watt and a 150 Watt light bulb. How much does it
cost to use all the lamps for 2.5 hours at $0.08/ kWh?
E-60
Answer:
$ .0248 or 2.48 cents
Explanation:
60 + 100 + 150 = 310 watts
for one hour = 310 watt- hr or .31 kw- hr
.31 kw-hr * .08 / kw-hr = .0248
pls help in these 2 questions
Answer:
Taking forces along the plane
F cos θ - M g sin θ -100 = M a net of forces along the plane
F = (M a + M g * .5 + 100) / .866 solving for F
F = (80 * 1.5 + 80 * 9.8 * .5 + 100) / .866 = 707 N
F = 707 N acting along the plane
Fn = F sin θ + M g cos θ forces acting perpendicular to plane
Fn = 707 * 1/2 + 80 * 9.8 * .866 = 1030 Newtons forces normal to plane
(this would give a coefficient of friction of 100 / 1030 = .097 = Fn)
A stone of mass 6kg is released from a height of 30m, calculate the velocity before the impact (take gravity=10m/s)
Answer:
23,49 m/s
Explanation:
Ep= Ek
mgh=mv2/2
6×10×30=6v2/2
1800=6 v2/2
6 v2=3600
v2 =600
v=24,49 m/s
The velocity of the stone, if a stone of mass 6 kg is released from a height of 30 m, is 24.5 m/s.
What is velocity?When something is moving, its velocity shows how quickly its location is changing as seen from a certain angle and as measured by a particular unit of time.
If a point moves a certain distance along its path in a predetermined length of time, its average speed throughout that time is equal to the distance traveled divided by the travel time. For instance, a train traveling 100 km in two hours is doing it at an average speed of 50 km/h.
Given:
The mass of the stone, m = 6 kg,
The height of the release, h = 30 m,
The value of gravity, g = 10 m/s,
Calculate the velocity using energy conservation as shown below,
The kinetic energy = potential energy (Energy conservation)
1/2 × 6 × v² = 6 × 10 × 30
v² = 300 × 2
v² = 600
v = √600
v = 10√6
v = 10 × 2.45
v = 24.49 or 24.5 m/s
Thus, the velocity is 24.5 m/s.
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A sound wave has a frequency of 265 hz and a wavelength measured at 1.3
m. the speed of the wave is 344.5 m/s.
how long will it take the wave to travel the length of a football field, which
is 91.4 m?
Answer:
V = f λ speed of wave in terms of frequency and wavelength
t = S / V time for wave to travel a distance S
t = 91.4 m / 344.5 m/s = .265 sec time to travel 91.4 m
Research indicates that high serotonin levels may increase aggression. please select the best answer from the choices provided t f
The statement 'research indicates that high serotonin levels may increase aggression' is FALSE.
What is serotonin?Serotonin is a chemical messenger (i.e., a hormone) used to transmit messages through the body.
Serotonin is generated by the nerve cells (neurons) of the central nervous system (CNS).In conclusion, the statement 'research indicates that high serotonin levels may increase aggression' is FALSE.
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What are the properties of mars
Answer:
Explanation:
Its surface is rocky, with canyons, volcanoes, dry lake beds and craters all over it. Red dust covers most of its surface. Mars has clouds and wind just like Earth
What can spectroscopes tell us about a space object?
A. provide imagery
B. calculate location
C. determine temperature, chemical composition, and speed
D. determine temperature, chemical composition, and size
Answer:
The answer is C.
Explanation:
Spectroscopy can be very useful in helping scientists understand how an object like a black hole, neutron star, or active galaxy produces light, how fast it is moving, and what elements it is composed of.Answer:
[tex]\huge\boxed{\sf Option \ 3}[/tex]
Explanation:
Spectroscope:The device used to tell the properties of the spectral lines in an electromagnetic spectrum is called spectroscope. Properties of spectroscope:For any space object, spectroscope tells:Type of element the object is made of.Temperature of object.Chemical composition.SpeedMagnetic and electric field.Spectroscope also can tell the light intensity and their wavelength.[tex]\rule[225]{225}{2}[/tex]
