What is true about radioactive isotopes of an atom?
They are less stable.
They are more abundant.
They are more scarce.
They are more stable.
Answer:
they are less stable
Explanation:
i took the test
A car is traveling at a speed of 45 km/h into town. It takes the car 2 hours to get there. How far has the car traveled?
Answer:
90 km
Explanation:
45 km per hr
2 hrs
45 x 2 = 90
90 km/2 hrs
Hope this helps!
A block of wood mass 0.60kg is balanced on top of a vertical port 2.0m high. A 10gm bullet is fired horizontally into the block and the embedded bullet land at a 4.0m from the base of the port. Find the initial velocity of the bullet.
Answer:
Mass of bullet is m=0.01kg
Mass of the block is M=4kg
Coefficient=0.25,distance=20m
So, let the speed of the block just after the bullet embedded in it be V and v be the speed of bullet before striking the block,
By applying conservation of momentum,
mv=(m+M)V
V=
M+m
mv
Explanation:
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The initial velocity of the bullet is 382 m/s
The given parameters;
mass of the wood, m₁ = 0.6 kgheight of the port, h = 2mass of the bullet, m₂ = 10 g = 0.01 kghorizontal distance traveled by the bullet, x = 4 mApply the principle of conservation of mechanical energy;
The maximum potential energy of the bullet-wood system at the top of the port = maximum kinetic energy of the system at the base of the port.
[tex]K.E_{max} = P.E_{max}\\\\\frac{1}{2} mv_{max}^2 = mgh_{max}\\\\v^2_{max} = 2gh_{max}\\\\v_{max} = \sqrt{2gh_{max}} \\\\v_{max} = \sqrt{2\times 9.8\times 2} \\\\v_{max} = 6.26 \ m/s[/tex]
Apply the principle of conservation of linear momentum to determine the initial velocity of the bullet;
let the initial velocity of the bullet = u₂[tex]m_1u_1 + m_2u_2 = v(m_1 + m_2)\\\\0.6(0) + 0.01(u_2) = 6.26((0.6 + 0.01)\\\\0.01u_2 = 3.819\\\\u_2 = \frac{3.819}{0.01} \\\\u_2 = 381.9 \ \approx 382 \ m/s[/tex]
Thus, the initial velocity of the bullet is 382 m/s
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An object is traveling with a velocity of 3.05 m/s. The object then accelerates at 2.82 m/s-over a
displacement of 18.4 m. What is its final velocity?
Answer:
Final velocity (v) = 5.148 m/s (Approx)
Explanation:
Given:
Initial velocity (u) = 3.05 m/s
Acceleration (a) = 2.82 m/s²
Displacement (s) = 18.4 m
Find:
Final velocity (v)
Computation:
v² = u² + 2as
v² = (3.05)² + 2(2.82)(3.05)
v² = 9.3025 + 17.202
v² = 26.5045
v = 5.148 m/s (Approx)
1. Why is it important to use units in any graph?
2. Why does any graph need a title on it?
Answer:
so its easier to understand for the reader
Explanation:
2) Labelling. Graphs are used to present data. They must be clearly labelled if the reader is to understand them. By labelling we are referring to the text inside the graph itself, and not the title.
A reversible power cycle operates with a thermal efficiency of 75%. The cycle receives energy input by heat from a thermal reservoir at 1200K. What is the temperature, in K, of the low temperature thermal reservoir
Answer:
The temperature of the low temperature thermal reservoir is 300 K.
Explanation:
All reversible power cycles are equivalent to the Carnot's cycle, whose equation for efficiency is:
[tex]\eta_{th} =1-\frac{T_{L}}{T_{H}}[/tex] (Eq. 1)
Where:
[tex]\eta_{th}[/tex] - Thermal efficiency, dimensionless.
[tex]T_{H}[/tex] - High temperature reservoir, measured in Kelvin.
[tex]T_{L}[/tex] - Low temperature reservoir, measured in Kelvin.
Now we proceed to clear the low temperature reservoir within:
[tex]\frac{T_{L}}{T_{H}} = 1-\eta_{th}[/tex]
[tex]T_{L} = (1-\eta_{th})\cdot T_{H}[/tex]
If [tex]\eta_{th} = 0.75[/tex] and [tex]T_{H} = 1200\,K[/tex], then:
[tex]T_{L} = (1-0.75)\cdot (1200\,K)[/tex]
[tex]T_{L} = 300\,K[/tex]
The temperature of the low temperature thermal reservoir is 300 K.
The bodies of many cars are designed to compress or crumple during an accident. Why are cars built with a crumple zone?
Define Transmission, reflection, refraction and diffraction
Answer:
transmission: the act or process by which something is spread or passed from one person or thing to another
reflection: when light from an object is reflected by a surface, it changes direction. It bounces off the surface at the same angle as it hits it. Smooth, shiny surfaces such as mirrors and polished metals reflect light well.
refraction: change in direction of a wave passing from one medium to another or from a gradual change in the medium
diffraction: various phenomena that occur when a wave encounters an obstacle or opening
Two charged objects, A and B, are exerting an electric force on each other. What will happen if the charge on A is increased?
А. The charge on B will decrease.
В. The charge on B will increase.
C. The electric force between A and B will decrease.
D. The electric force between A and B will increase.
Answer: The forces acting on both of them will increase in magnitude.
Explanation:
According to Coulomb's law, the electrostatic force between two bodies is proportional to the product of their two charges. If the charge on A is increased this product increases in size (it must have been non-zero to begin with, since there was a force between them at first). Thus, the force between them rises.
Answer:
d. seems like the right answer.
Explanation:
Calculate the acceleration of a student riding his bicycle in a straight line that speeds up from 4 m/s to 6 m/s in 5 seconds.
A particular car can go from rest to 90 km/h in 10 s. What is its acceleration? (Report your answer in km/h*s)
Answer: 9 km/h
Explanation:i’m pretty sure
Answer:
Well, it depends on the type of car but a regular car like a toyota 4x4 only goes at 5k/h if the car starts when complete rest
3 general relevant psychology related problems at present
Answer:
Explanation:
Scientific research conducted by psychologists, organized by topics here, can inform and guide those seeking help with issues that affect their professional lives, family relationships and emotional wellness.Tips for choosing a psychotherapist and answers to financial questions related to therapy.
When faced with important events (stressors) which are threatening or very hard to, psychological symptoms of stress include anxiety and tension, uncontrollable. In general, this refers to high levels of suspicion and mistrust, usually seen in this psychological condition is associated with acute physical sickness
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A box weighing 52.4 N is sliding on a rough horizontal floor with a constant friction force of magnitude LaTeX: ff. The box's initial speed is 1.37 m/s and it stops after 2.8 s. Determine the magnitude of the friction force exerted on the box.A box weighing 52.4 N is sliding on a rough horizontal floor with a constant friction force of magnitude LaTeX: ff. The box's initial speed is 1.37 m/s and it stops after 2.8 s. Determine the magnitude of the friction force exerted on the box.
Answer:
The magnitude of the friction force exerted on the box is 2.614 newtons.
Explanation:
Since the box is sliding on a rough horizontal floor, then it is decelerated solely by friction force due to the contact of the box with floor. The free body diagram of the box is presented herein as attachment. The equation of equilbrium for the box is:
[tex]\Sigma F = -f = m\cdot a[/tex] (Eq. 1)
Where:
[tex]f[/tex] - Kinetic friction force, measured in newtons.
[tex]m[/tex] - Mass of the box, measured in kilograms.
[tex]a[/tex] - Acceleration experimented by the box, measured in meters per square second.
By applying definitions of weight ([tex]W = m\cdot g[/tex]) and uniform accelerated motion ([tex]v = v_{o}+a\cdot t[/tex]), we expand the previous expression:
[tex]-f = \left(\frac{W}{g} \right)\cdot \left(\frac{v-v_{o}}{t}\right)[/tex]
And the magnitude of the friction force exerted on the box is calculated by this formula:
[tex]f = -\left(\frac{W}{g} \right)\cdot \left(\frac{v-v_{o}}{t}\right)[/tex] (Eq. 1b)
Where:
[tex]W[/tex] - Weight, measured in newtons.
[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.
[tex]v_{o}[/tex] - Initial speed, measured in meters per second.
[tex]v[/tex] - Final speed, measured in meters per second.
[tex]t[/tex] - Time, measured in seconds.
If we know that [tex]W = 52.4\,N[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]v_{o} = 1.37\,\frac{m}{s}[/tex], [tex]v = 0\,\frac{m}{s}[/tex] and [tex]t = 2.8\,s[/tex], the magnitud of the kinetic friction force exerted on the box is:
[tex]f = -\left(\frac{52.4\,N}{9.807\,\frac{m}{s^{2}} } \right)\cdot \left(\frac{0\,\frac{m}{s}-1.37\,\frac{m}{s} }{2.8\,s} \right)[/tex]
[tex]f = 2.614\,N[/tex]
The magnitude of the friction force exerted on the box is 2.614 newtons.
A coil is wrapped with 206 turns of wire on the perimeter of a circular frame (of radius 31 cm). Each turn has the same area, equal to that of the frame. A uniform magnetic field is directed perpendicular to the plane of the coil. This field changes at a constant rate from 23 mT to 54 mT in 24 ms. What is the magnitude of the induced average E in the coil, over the time interval 24 ms during which the field changes? Answer in units of V.
Answer:
E = -80.33 V
Explanation:
For this exercise we use Faraday's law of induction
E = - N d[tex]\phi _{B}[/tex] / dt
where the magnetic flux is
\phi _{B} = B A cos θ
In the exercise they indicate that the magnetic field is perpendicular to the coil, therefore the normal of the coil area and the field has the same direction, consequently the angle is zero. Since the area is constant
E = - N A dB / dt
let's look for each term
a =π r²
they tell us that the variation in the field is linear
dB / dT = (B_f-B₀) / t
we substitute
E = - N (π r²) (B_f -B₀) / t
let's calculate
E = - 206 π 0.31² (54 - 23) 10⁻³ / 24 10⁻³
E = -80.33 V
Stokes’ law describes sedimentation of particles in liquids and can be used to measure viscosity. Particles in liquids achieve terminal velocity quickly. One can measure the time it takes for a particle to fall a certain distance and then use Stokes’ law to calculate the viscosity of the liquid. Suppose a steel ball bearing (density 7.8 \times 10^3~\text{kg/m}^37.8×10 3 kg/m 3 and diameter 3.0~\text{mm}3.0 mm) is dropped in a container of motor oil. It takes 12 s to fall a distance of 0.60 m. Calculate the viscosity of the oil.
Answer:
The viscosity is [tex]\eta = 0.76243 \ kg/ m \cdot s [/tex]
Explanation:
From the question we are told that
The density is [tex]\rho = 7.80 *10^{3} \ kg/m^3[/tex]
The diameter is [tex]d = 3.0 \ mm =0.003 \ m[/tex]
The time taken is [tex]t = 12 \ s[/tex]
The distance covered is [tex]d = 0.60 \ m[/tex]
Generally the velocity of the ball is
[tex]v = \frac{d}{t}[/tex]
=> [tex]v = \frac{0.60}{12}[/tex]
=> [tex]v = 0.05 \ m/s [/tex]
Generally the mass of the steel ball is
[tex]m = \rho * V[/tex]
Here V is the volume and this is mathematically represented as
[tex]V = \frac{4}{3} * \pi * [\frac{d}{2} ]^3[/tex]
=> [tex]V = \frac{4}{3} * 3.142 * [\frac{0.003}{2} ]^3[/tex]
=> [tex]V = 1.414 *10^{-8} \ m^3[/tex]
So
[tex]m = 7.80 *10^{3} * 1.414 *10^{-8}[/tex]
[tex]m = 0.00011 \ kg [/tex]
Generally the viscosity is mathematically represented as
[tex]\eta = \frac{m * g}{6\pi * r * v }[/tex]
Here r is the radius represented as
[tex]r = \frac{d}{2}[/tex]
=> [tex]r = \frac{0.003}{2}[/tex]
[tex]r = 0.0015 \ m [/tex]
So
[tex]\eta = \frac{0.00011 * 9.8}{6 * 3.142 * 0.0015 * 0.05 }[/tex]
=> [tex]\eta = 0.76243 \ kg/ m \cdot s [/tex]
3. Pencils should not be used inside the computer to change the setting of switches or to
and
pry off jumpers because the tip contains lead which can act as a
may damage the computer Components.
Answer: True
Explanation:
Pencils indeed should not be used as tools when working inside a computer because it is made of Lead.
Lead is a conductor of electricity and as such if it is left inside the computer at even miniscule quantities, it can redirect electricity and damage components in the process.
If one wants to work inside a computer, it is best to use tools like tweezers and needle-nose pliers.
Due to the presence of graphite(A good conductor of electricity), Pencils should not be used inside the computer to change the setting of switches.
What is the meaning of conductors?The conductors are the materials that can allow electricity and heat to pass through them.
Since the pencils are made up of graphite which is a good conductor of electricity. When we use pencils to do something inside the computer circuits and if some portion of the graphite remains on the circuit board.
Now due to the good conducting property of the graphite, it will allow the current to flow and the short circuit of the circuit board can take place which will damage the computer.
Thus due to the presence of graphite(A good conductor of electricity). Pencils should not be used inside the computer to change the setting of switches.
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The derivative of a position function is a velocity function. The derivative of a velocity function is an acceleration function. A particle moves along a straight line. The distance of the particle from the starting point at time t is given by the function: s=t5−6t4 Find the value of t (other than 0 ) at which the acceleration is equal to zero. 6
Answer:
3.6secsExplanation:
Given the distance of the particle from the starting point at time t is given by the function: s=t⁵−6t⁴
velocity v(t) = ds/dt
[tex]v(t) = 5t^{5-1}-4(6)t^{4-1}\\v(t) = 5t^4-24t^3\\[/tex]
Next is to get the acceleration function:
[tex]a(t) = 4(5)t^{4-1}-3(24)t^{3-1}\\a(t) = 20t^3-72t^2[/tex]
Next is to get the value of t at which the acceleration is equal to zero
[tex]a(t) = 20t^3-72t^2\\0 = 20t^3-72t^2\\20t^3-72t^2 = 0\\t^2(20t-72) = 0\\t^2 =0 \ and \ 20t-72 = 0[/tex]
Since t ≠ 0, hence;
20t -72 = 0
20t = 72
t = 72/20
t = 3.6secs
Hence the value of t (other than 0 ) at which the acceleration is equal to zero is 3.6secs
which can occur in a physical change
Answer:
A physical change involves a change in physical properties. Examples of physical properties include melting, transition to a gas, change of strength, change of durability, changes to crystal form, textural change, shape, size, color, volume and density.
Explanation:
What volume is represented by each small tick mark ? Help !!!
Answer:
In the taller, skinnier cylinder, each tick mark represents 2, while in the larger one, each tick mark represents 50.
Explanation:
If you count the tick marks between each big number, then you can divide, and figure out what amount each tick mark represents.
15) A 1720 kg car accelerates at a rate of 3.0 m/s2. How much force is the car's engine producing? (use the formula F=ma
Answer:
The answer is 5160 NExplanation:
To find the force acting on an object given it's mass and acceleration we use the formula
Force = mass × accelerationFrom the question
mass = 1720 kg
acceleration = 3.0 m/s²
We have
Force = 1720 × 3
We have the final answer as
5160 NHope this helps you
In positron-emission tomography (PET) used in medical research and diagnosis, compounds containing unstable nuclei that emit positrons are introduced into the brain, destined for a site of interest in the brain. When a positron is emitted, it goes only a short distance before coming nearly to rest. It forms a bound state with an electron, called "positronium", which is rather similar to a hydrogen atom. The binding energy of positronium is very small compared to the rest energy of an electron. After a short time the positron and electron annihilate. In the annihilation, the positron and the electron disappear, and all of their rest energy goes into two photons (particles of light) which have zero mass; all their energy is kinetic energy. These high energy photons, called "gamma rays", are emitted at nearly 180° to each other. What energy of gamma ray (in MeV, million electron volts) should each of the detectors be made sensitive to? (The mass of an electron or positron is 9 × 10-31 kg. 1 eV = 1.6 × 10-19 joules.
Answer:
Energy of gamma ray = 506250 eV
Explanation:
We are told that the mass of an electron or positron is 9 × 10-31 kg.
This means that their energies will be the same.
Thus; E_e = E_p
Now, since electron and positron annihilate to form gamma(γ) particle, then using work energy principle, we have;
E_γ + E_γ = E_e + E_p
Thus;
2E_γ = E_e + E_p
Since E_e = E_p, we now have;
2E_γ = 2E_e
Thus;
E_γ = E_e
Since all the energy of the electron is converted, then from Einstein's relativity theory, this implies that;
E_e = mc²
c is speed of light = 3 × 10^(8) m/s
And m is given as 9 × 10^(-31) kg
Thus;
E_e = 9 × 10^(-31) × (3 × 10^(8))^(2)
E_e = 810 × 10^(-16) J
Since E_γ = E_e
Thus;
E_γ = 810 × 10^(-16) J
We are given that; 1.6 × 10^(-19) J = 1eV
Thus; 810 × 10^(-16) J gives;
(810 × 10^(-16) × 1)/(1.6 × 10^(-19)) = 506250 eV
Suggest one reason why the bricklayer needs a higher energy diet than the computer operator
Answer:
he needs more because he is doing more exercise this means he is working his body more and he needs more energy than someone he is sitting in an office. The computer operator would not need as much energy as the brick layer.
Why can concave mirror is used in cosmetic mirror
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A radio station sending out a radio wave of frequency 100.5MHz at velocity of 3×10⁸ms⁻¹. At what wavelength is the radio station broadcasting
An airplane flying at 119 m/s is accelerated uniformly at the rate of 0.5 m/s2 for 10
seconds. What is its final speed?
Answer:
124m/s
Explanation:
v=u+at
v=119+(0.5×10)
v=119+5
v=124m/s
HELPP PLEASEEE Which issue is not a challenge an organism encounters?
A getting energy
B reproducing
C maintaining structure
D regenerating arms
Answer:
regenerating arms....