An alpha particle is a Helium nucleus that is emitted during alpha decay, this meant that alpha decay results in the amission of a Positively charged helium ion.
A 61 −kg ice skater coasts with no effort for 50 m until she stops. If the coefficient of kinetic friction between her skates and the ice is μk=0.10 , how fast was she moving at the start of her coast?
The 61 Kg ice skater was moving with a velocity of 9.9 m/s at the start of her coast.
How do I determine the initial velocity ?We'll begin by calculating the force. This can be obatined as follow:
Mass (m) = 61 KgAcceleration due to gravity (g) = 9.81 m/s²Normal reaction (N) = mg = 61 × 9.8 = 597.8 NCoefficient of kinetic friction (μK) = 0.10Force (F) = ?F = μKN
F = 0.1 × 597.8
F = 59.78 N
Next, we shall obtain the deceleration. This can be obtained as follow:
Force (F) = 59.78 NMass (m) = 61Deceleration (a) = ?a = -F / m (since the skater is coming to rest)
a = -59.78 / 61
a = -0.98 m/s²
Finally, we shall determine the initial velocity. This can be obtained as follow:
Distance (s) = 50 mFinal velocity (v) = 0 m/sDeceleration (a) = -0.98 m/s²Initial velocity (u) = ?v² = u² + 2as
0² = u² + (2 × -0.98 × 50)
0 = u² - 98
Collect like terms
u² = 0 + 98
u² = 98
Take the square root of both sides
u = √98
u = 9.9 m/s
Thus, the skater was moving with a velocity of 9.9 m/s
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A rock sample has a mass of 6 kg and a volume of 0.002 m3. Calculate the density of this rock sample.
The density of the rock sample is 3000 kg/m³.
Density is an important property of matter because it can be used to determine the weight of an object. For example, if you know the density of a rock sample and its volume, you can calculate its weight by multiplying the density by the volume. Density can also be used to determine the composition of a material. For example, if you know the densities of different materials, you can identify the material of a rock sample by measuring its density.
Density is a measure of how much mass is contained in a given volume.. The calculation of the density of the rock sample:
Density = Mass / Volume
Density = 6 kg / 0.002 m³
Density = 3000 kg/m³
As a result, the rock sample has a density of 3000 kg/m³.
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A plane's average speed between 2 cities is 800 km/hr. If the trip takes 4.5 hours howfar does the plane fly?
Considering the average velocity can be written as:
[tex]v=\frac{\Delta s}{\Delta t}[/tex]We can isolate the distance, and we get:
[tex]\Delta s=v*\Delta t\rightarrow\Delta s=800*4.5=3600km[/tex]Then, the distance the plane flew is 3600km
Draw In figure what the compass needles would show if that current is as shown in the figure. Make the arrow the “north” direction. (Please refer to picture)
The direction of the magnetic field around a current-carrying conductor is given by the right-hand thumb rule. In the figure, the direction of the flow of the current is into the plane of the paper.
Therefore the needles of the compass would align as,
In the above figure, the arrowheads indicate the north direction.
Ultraviolet light has shorter wavelengths and higherfrequencies than visible light.TRUEFALSE
Ultraviolet light has shorter wavelengths and higher frequencies than visible light.
The answer is TRUE
How long would it take to pass 700 C of charge through a toaster drawing 10 A of current? How many electrons would pass through the toaster in this time?
Given that the charge of the toaster is q =700 C
The current of the toaster is I = 10 A
We have to find the time and number of electrons.
Time can be calculated by the formula,
[tex]t=\frac{q}{I}[/tex]Substituting the values, the time will be
[tex]\begin{gathered} t=\frac{700}{10} \\ =70\text{ s} \end{gathered}[/tex]The number of electrons can be calculated by the formula,
[tex]n=\frac{q}{e}[/tex]Here, n is the number of electrons
and e is the charge of the electron whose value is
[tex]1.6\text{ }\times10^{-19}\text{ C}[/tex]Substituting the values, the number of electrons will be
[tex]\begin{gathered} n\text{ = }\frac{700}{1.6\times10^{-19}} \\ =4.375\text{ }\times10^{-17} \end{gathered}[/tex]A motorcycle has a constant acceleration of 3.74 m/s2. Both the velocity and acceleration of the motorcycle point in the same direction. How much time is required for the motorcycle to change its speed from (a)21.5 to 31.5 m/s, and (b)51.5 to 61.5 m/s?(a)Number ______ Units_________(b)Number ______ Units_________
Since the acceleration is constant we know that it is given by:
[tex]a=\frac{v_f-v_0}{t}[/tex]from where we have that:
[tex]t=\frac{v_f-v_0}{a}[/tex]once we have this equation we can determine the time by plugging the values of the acceleration and velocities.
a)
In this case we have that:
[tex]t=\frac{31.5-21.5}{3.74}=2.67[/tex]Therefore it takes 2.67 s.
b)
In this case we have that:
[tex]t=\frac{61.5-51.5}{3.74}=2.67[/tex]Therefore it takes 2.67 s.
If there is a source voltage of 12 volts with a 2.5 volt drop over the LED, and an intended current of 100 mA, what size resistor should be used?
Given:
A voltage source has a voltage of 12 V.
A voltage drop over the LED is 2.5 V.
The current in the circuit is 100 mA.
To find:
The resistance of the resistor should be used.
Explanation:
LED is a forward-biased PN junction that emits light. The voltage drop over the LED is 2.5 V.
The voltage source has a voltage of 12 V.
Hence, the total voltage in the circuit = 12 V - 2.5 V = 9.5 V
The resistance of the circuit in the forward biased is almost equal to zero. Let the resistance in the circuit be R.
Thus, the total resistance in the circuit = 0 + R = R
The current in the circuit is = 100 mA = 0.1 A
The resistance R of the circuit can be calculated as:
[tex]R=\frac{V}{I}[/tex]Here, V is the voltage in the circuit and I is the current in the circuit.
Substituting the values in the above equation, we get:
[tex]\begin{gathered} R=\frac{9.5\text{ V}}{0.1\text{ A}} \\ \\ R=95\text{ }\Omega \end{gathered}[/tex]Final answer:
Hence, a resistor of 95 Ω should be used in the circuit.
People weigh less on the moon than on the Earth because:the moon is smaller and has less gravity to pull on you.the Earth has less gravity than the Moon.people weigh the same on the moon as they do on Earth.the moon is magnetized.
Given
People weigh less on the moon than on the Earth
To find
The correct reason for the given statement
Explanation
The moon has much lesser mass than that of the earth. It is also just 60 percent as dense as the earth. So the gravitational pull on the moon is less than on the earth and thus people weigh less on the moon
Conclusion
The correct reason is
the moon is smaller and has less gravity to pull on you.
Convert 500BTU/ft.s.F to g.cal/cm^2.s.°C
The requirement of the prompt is for 500 British Thermal Units /Calories (Cal) to be converted to Gram Calories. Hence, 500 BTU (cal) = 126,082cm²
What is a British Thermal Unit?A British thermal unit is a heat unit defined as the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit. It is also one of the customary units used in the United States.
To covert 500 BTU, one must note that according to established scientific metrics.:
1 BTU = 252.164 Gram (Cal).
Hence,
500 BTU = 252.164 x 500
= 126,082 cm²
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Derek leaves his physics book on top of a drafting table that is inclined at a 35° angle. The table exerts a force on the book of 18 Newtons, and the force of gravity is 22 Newtons. If the Force of friction acting on the book is 11 Newtons, what is the Net Force on the book?
The net force on the book is equal to 1.61 N.
What is the net force?The net force on the object can be defined as the vector sum of all the forces together. Net force becomes resultant force and shows the same effect on the rotational motion as all actual forces.
Given, the angle of the book with the table, α = 35°
The force of friction, f = 11N
The normal force acting on the book, N = 18N
The force of gravity, W = 22 N
The net force along the table is F₁ = Wsinα - f
F₁= 22× sin35° - 11
F₁ = 1.6 N
The net force perpendicular to table is F₂ = W cosα -N
F₂= 22×cos35° -18
F₂ = 0.021 N
The net force on the book is [tex]F_{net} = \sqrt{F_1^2+F_2^2}[/tex]
[tex]F_{net} = \sqrt{(1.6)^2+(0.021)^2}[/tex]
[tex]F_{net} = 1.61N[/tex]
Therefore, the net force on the book is equal to 1.61 Newtons.
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how far away is a star if it takes light 12.5 years to reach the earth?
What is the kinetic energy of a 2.0 kg object moving at 5 m/s?
Let's put the given values into the formula below and get the result;
[tex]K.E=\frac{1}{2}mv^2[/tex]We know the numerical value of speed. We also know the mass. We can jump straight to the conclusion.
[tex]K.E=\frac{1}{2}(2kg)(5m/s)^2[/tex][tex]=\frac{1}{2}(2kg)(25m^2/s^2)[/tex][tex]=25m^2/s^2=25J[/tex]The Kinetic Energy is 25J.
If we want to accelerate an object, we must apply force on it, after applying Force some work has to be done in which energy should be transferred to the object. The energy is known as kinetic energy. The kinetic energy always depends on the mass and the velocity. It is denoted as K and the Si unit is Joules (J).
To calculate the Kinetic Energy,
K= 1/2 mv^2
m = mass
v = velocity
K = kinetic energy
In solving the above equation,
K = 1/2 x2 x 5^2
K = 5x5
K = 25
The Kinetic Energy is 25J.
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The role or purpose of the battery in a circuit is to ____. Choose three.Group of answer choicesa) supply electric charge so that a current can existb) supply energy to the chargec) move the charge from the - to the + terminal of the batteryd) transform energy from electrical energy into light energye) establish an electric potential difference between the + and - terminalsf) replenish the charge which is lost in the light bulbg) offer resistance to the flow of charge so that the light bulb can get hot
Given:
The battery is connected to a circuit.
To find:
The purpose of the battery in the circuit
Explanation:
A battery is a source of energy in a circuit. The battery provides a push or a voltage to get the current flowing in a circuit.
Hence, the purposes are
b) supply energy to the charge
e) establish an electric potential difference between the + and - terminals
f) replenish the charge which is lost in the light bulb
my choice1A child pushes a toy truck up an inclined plane. The lifting force is...Select one:ut ofO a. the weight of the truck.O b. the length of the inclined plane.O c. the force the child uses to push the truck.uestionO d. equal to the total amount of work done.
When pushing a toy truck up an inclined plane, the force that makes the truck goes up is the force that the child uses to push the truck. (The force that pushes
Therefore the correct option is C.
It is not possible to derive an equation of motion for uniform acceleration without a time variable. Is this true or false?
The third equation of motion is given as,
[tex]v^2=u^2+2as[/tex]Here, v is the final velocity, u is the initial velocity, a is the acceleration and s is displacement.
The expression for the acceleration is given as,
[tex]a=\frac{v^2-u^2}{2s}[/tex]In the above expression, the acceleration of the body is not a function of the time variable. Therefore, it is possible to derive an equation of motion for uniform acceleration without a time variable. Hence, the given statement is false.
What is the frequency of a photon of EMR with a wavelength of 2.55x10*³m?1.18x1011 Hz8.50x10 12 Hz7.65x105 Hz1.18x105 Hz
In order to solve this equation, we will need to use the formula
[tex]f=\frac{c}{\lambda}[/tex]where f = frequency, c is the speed of light and lamda is wavelength
c = 3x10^8 m/s
lamda = 2.55x10^-3 m
f = (3x10^8)/(2.55x10^-3) = 1.18x10^11 1/s
A projectile is fired at an upward angle of 55.0 ∘ from the top of a 155 m cliff with a speed of 165 m/s .
a)What will be its speed when it strikes the ground below? (Use conservation of energy and neglect air resistance.)
A projectile is fired at an upward angle and the speed of the object when it strikes the ground below will be 434.5 m/s.
What is Projectile motion?A projectile is an object or particle that is thrown toward the surface of the Earth and moves along a curved route only under the influence of gravity. Galileo demonstrated that this curving path was a parabola, but in the unique situation where it is hurled straight up, it may also be a straight line.
According to the question,
[tex]h=v_0_yt+1/2gt^2[/tex]
-155 m = (165 × sin 55°)t - 0.5(9.8)t²
-155 = 135.16t - 4.9 t²
4.9 t² - 135.16t - 155 = 0
t = 27.5 seconds.
Now, the speed of the object when it strikes the ground will be,
[tex]v_f=v_i+gt[/tex]
= 165 + (9.8)(27.5)
[tex]v_f[/tex] = 434.5 m/s.
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Round the answer for each problem to the correct number of significant figures.
a. (7.31 × 104) + (3.23 × 103)
b. (8.54 × 10–3) – (3.41 × 10–4)
c. 4.35 dm × 2.34 dm × 7.35 dm
d. 4.78 cm + 3.218 cm + 5.82 cm
e. 38,736 km ÷ 4784 km
After solving each problem to correct the number of significant figures :
(a) 76330
(b) 8199 × 10⁻³
(c) 74.81 dm.
(d) 13.8 cm
(e) 8.09 km
What is an Equation?Equations are mathematical expressions that have two algebraic expressions on either side of an equals (=) sign. The expressions on the left and right are shown to be equal to one another, demonstrating this relationship. L.H.S. = R.H.S. (left hand side = right hand side) is a fundamental mathematical formula.
According to the question,
(a) (7.31 × 10⁴) + (3.23 × 10³)
(73100) + (3230) = 76330
(b) (8.54 × 10⁻³) – (3.41 × 10⁻⁴)
= 8199 × 10⁻³
(c) 4.35 dm × 2.34 dm × 7.35 dm
= 74.81 dm.
(d) 4.78 cm+3.218 cm+5.82 cm
= 13.8 cm
(e) 38,736 km ÷ 4784 km
= 8.09 km
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A person is at the top of a slide with 200 J of potential energy. Explain what happens to the energy as they slide down.
Answer:
the person changes from potential energy , to kinetic energy back to potential
The hydrogen-to-helium ratio is an important piece of evidence for the Big Bang Theory. What is the minimum hydrogen-helium ratio observed?A. 4:1B. 3:1C. 2:1
Correct answer is option B.
Answer:
3:1
Explanation:
A person is running at a velocity vv. By which factor would they need to increase their speed in order to double their kinetic energy?
The kinetic energy is given by:
[tex]K=\frac{1}{2}mv^2[/tex]If we want to double it then we have:
[tex]2(\frac{1}{2}mv^2)=\frac{1}{2}m(\sqrt[]{2}v)^2[/tex]Therefore the speed has to increas by a factor of square root of 2
Hey! I really need help with this question please :)
Answer: B
Explanation:
The formula for calculating the efficiency of a heat engine is expressed as
Efficiency = useful work done/Heat energy supplied x 100
From the information given,
Heat energy supplied = 500
useful work done = 50
Efficiency = 50/500 x 100
Efficiency = 10%
Two children are riding on a merry-go-round. Child A is at a greater distance from the axis of rotation than child B. Which child hasthe larger linear displacement?Select one:a. There is not enough information given to answer the question.b. Child Ac. They have the same non-zero linear displacementd. Child Be. They have the same zero linear displacement.
The linear displacement in a rotation is given by:
[tex]s=r\theta[/tex]where r is the distance from the axis of rotation and theta is the angular displacement.
Since the linear displacement is proportional to the radius we conclude that child A has a larger linear displacement.
Suppose you stand with one foot on ceramic flooring and one foot on a wool carpet,
making contact over an area of 80.0cm2 with each foot. Both the ceramic and the
carpet are 2.00 cm thick and are 10.0ºC on their bottom sides. At what rate must
heat transfer occurs from each foot to keep the top of the ceramic and carpet at
33.0ºC?
The rate of heat transfer from each foot to keep the top of the ceramic and carpet at the desired temperature is 27.6 J/s.
What is thermal heat transfer?
Thermal heat transfer is defined as the movement of heat across the border of the system due to a difference in temperature between the system and its surroundings.
The rate at which heat transfer occurs from each foot to keep the top of the ceramic and carpet at the given temperature is calculated as follows;
Q/t = kA(T₂ - T₁)/d
where;
Q/t is the rate of heat transfer
k is heat transfer coefficientT₂ is the final temperatureT₁ is the initial temperatured is the distance between the wool and ceramics
The heat transfer coefficient of human skin = 0.3 W / m⁰C
Area = 80 cm² = 0.008 m²
thickness, d = 2 cm = 0.02 m
change in temperature, = 33⁰ C - 10 ⁰C = 23 ⁰C
Q/t = (0.3 x 0.008 x 23) / (0.002)
Q/t = 27.6 W = 27.6 J/s
Thus, the rate of heat transfer from each foot to keep the top of the ceramic and carpet at the desired temperature is 27.6 J/s.
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how far will you go (km) in 3 min traveling 60 km/hr?
We will have the following:
First, we transform minutes to hours, that is:
[tex]3\min \cdot\frac{1h}{60\min }=0.05h[/tex]Now, we determine the distance traveled:
[tex]d=(60km/h)(0.05h)\Rightarrow d=3km[/tex]So, you will go 3km.
The pressure is greater at the bottom of the bucket filled with water ,why?
QUESTION 22As the rocket moves from position "b" to posisition "c", its speed is:constant.O continuously increasing.O continuously decreasing.increasing for a while and constant thereafter.constant for a while and decreasing thereafter.
The rocket movement due to the direction between a and b, and turning on the engine, movement is described by E image
Is continuously increasing, the force is constant and the acceleration too, which means that the speed continues increasing
Block 1 has a mass of 12 kg is moving to the right on a levelsurface at a speed of 2 m/s. Block 2 has a mass of 2.5 kg andis at rest on the surface. Block 1 collides with block 2, causingblock 2 to move to the right with a speed of 4 m/s. How fast,and in what direction, is block 1 moving after the collision?
Given:
The mass of block 1, m₁=12 kg
The mass of block 2, m₂=2.5 kg
The velocity of block 1 before the collision, u=2 m/s
The velocity of block 2 after the collision, v₂=4 m/s
To find:
The velocity of block 1 after the collision.
Explanation:
From the law of conservation of momentum, the total momentum of the blocks before the collision will be equal to the total momentum of the blocks after the collision.
Thus,
[tex]m_1u=m_1v_1+m_2v_2[/tex]Where v₁ is the velocity of block 1 after the collision.
On rearranging the above equation,
[tex]v_1=\frac{m_1u-m_2v_2}{m_1}[/tex]On substituting the known values,
[tex]\begin{gathered} v_1=\frac{12\times2-2.5\times4}{12} \\ =1.17\text{ m/s} \end{gathered}[/tex]The positive sign of the velocity indicates that block 1 will continue to move to the right.
Final answer:
The velocity of block 1 after the collision will be 1.17 m/s and its direction is to the right.
The nearest star to the Earth (other than the Sun) is about 4.0 lightyears away. A lightyear, ly, is the distance light travels in one year. Voyager 1 is traveling at 38,500 miles per hour. How long will it take Voyager 1 to reach the nearest star in years?
First, let's convert the distance of 4 lightyears to miles:
[tex]4\text{ ly}=4\cdot5.879\cdot10^{12}\text{ miles}=23.516\cdot10^{12}\text{ miles}[/tex]Now, let's find the time required:
[tex]\begin{gathered} distance=speed\cdot time\\ \\ 23.516\cdot10^{12}=38500\cdot t\\ \\ t=\frac{23.516\cdot10^{12}}{38500}\\ \\ t=6.10805\cdot10^8\text{ hours} \end{gathered}[/tex]Then, we need to convert from hours to years:
[tex]6.10805\cdot10^8\text{ hours}=\frac{6.10805\cdot10^8}{8760}=6.97266\cdot10^4\text{ years}[/tex]Therefore it will take approximately 69727 years.
