Answer:
Explanation:
v = u + at
Let Up be the positive direction
v(2) = 24 + (-9.8)(2) = 4.4 m/s Positive result means Upward
v(3) = 24 + (-9.8)(3) = -5.4 m/s Negative result means Downward
The motor of an electric drill has a power input of 1200 W. How much work 3 points
is done by the drill in a time of 2 minutes? *
Your answer
This is a required question
Answer:
Explanation:
1 Watt = 1 J/s
1200 J/s(2 min)(60 s/min) = 144 KJ
why does gas have the most energy but moves the slowest
Gases have heavier molecules. Since all gases have the same average kinetic energy at the same temperature, lighter molecules move faster and heavier molecules move slower on average.
3. A car travelling at 12 m/s into a stationary truck of about 10 times the cars mass. a. If the collision was completely inelastic, what velocity would the two travel at if the stuck together? b. If the collision was completely elastic, what would be the velocities of the car and truck after the collision? c. In order to exert a force of only 3500N on the truck during the collision, how much time would the collision have to take?
(a) The final velocity of the two vehicles if the collision was inelastic is 1.1 m/s.
(b) For the elastic collision, the final velocity of the car is 9.81 m/s backwards and the final velocity of the truck is 2.19 m/s forward.
(c) The time taken to exert the given force is 0.00625 m (s).
The given parameters;
Initial velocity of the car, u₁ = 12 m/sInitial velocity of the truck, u₂ = 0Mass of the car, = mMass of the truck, = 10m(a) The final velocity of the two vehicles if the collision was inelastic is calculated as follows;
[tex]m_1 u_1 + m_2u_2 = v(m_1+ m_2)\\\\12m + 10m(0) = v(m + 10m)\\\\12m = v(11m)\\\\v = \frac{12m}{11m} \\\\v = 1.1 \ m/s[/tex]
(b) The final velocity of the two vehicles if the collision was elastic is calculated as follows;
[tex]m_1 u_1 + m_2u_2 = m_1v_1 + m_2v_2\\\\\12m \ + \ 10m(0) = mv_1 + 10mv_2\\\\12m = m(v_1 + 10v_2)\\\\12 = v_1 + 10 v_2\ \ - --(1)[/tex]
Apply one-directional velocity equation:
[tex]u_1 +v_1 = u_2 + v_2\\\\12 + v_1 = 0 + v_2\\\\12+ v_1 = v_2 \ \ --- (2)[/tex]
Substitute the value of [tex]v_2[/tex] into equation (1);
[tex]12 = v_1 + 10(12 + v_1)\\\\12= v_1 + 120 + 10v_1\\\\12- 120 = 11v_1\\\\-108 = 11v_1\\\\v_1 = \frac{-108}{11} \\\\v_1 = -9.81 \ m/s\\\\[/tex]
Solve for [tex]v_2[/tex];
[tex]v_2 = 12 + v_1\\\\v_2 = 12 - 9.81\\\\v_2 = 2.19 \ m/s[/tex]
Thus, for the elastic collision, the final velocity of the car is 9.81 m/s backwards and the final velocity of the truck is 2.19 m/s forward.
(c)
The change in the momentum of the truck is calculated as;
[tex]\Delta P = m_2(v_2 - u_2)\\\\\Delta P = 10m(2.19)\\\\\Delta P = 21.9m[/tex]
The time taken to exert the given force is calculated as follows;
[tex]Ft = \Delta P\\\\t = \frac{\Delta P}{F} \\\\t = \frac{21.9 \ m}{3500} \\\\t = 0.00625 \ m (seconds)[/tex]
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A tightly sealed house has a large ceiling fan that blows air out of the house and into the attic. The owners turn the fan on and forget to open any windows or doors. What happens to the air pressure in the house after the fan has been on for a while, and does it become easier or harder for the fan to do its job
Answer:
Assuming the attic is ventilated to the open air the air pressure inside the house gets lower and the fan job becomes easier. It will speed up because while the pressure differential across the fan is increased, the mass of air being moved has decreased.
This can be verified by running a household vacuum cleaner in hose mode. With the hose open and air moving through it, the motor speed will be at a certain level producing a certain noise pitch . Placing your hand over the hose end will decrease the pressure in the hose, reduce the volume of air moving and you will hear an increase in motor pitch as it speeds up under lower load conditions.
The area inside the vacuum hose is akin to the inside of a well sealed house with an attic fan running.
In the physical sciences, pressure is compressive stress at quite a point within a confined fluid or the perpendicular force per unit area.
What is Pressure?The force exerted perpendicularly to an object's surface per unit area across which that force is dispersed is termed as pressure. In relation to the surrounding pressure, gauge pressure is the pressure.
The air pressure within the house decreases and the fan's task gets simpler if the attic is aired to the outside air. It will increase because the amount of air being moved is much less, while the pressure difference across the fan is greater.
Running a home vacuum in hose mode will demonstrate this. The motor speed will be maintained at a set level, producing a specific noise pitch, with the duct open and air flowing through it. You will notice an increase in motor pitch when it speeds up under reduced load situations by placing your finger over the hose end, which will also lower the pressure in the hose and limit the amount of air moving.
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Check if correct or not:
Directions: Using what you learned about energy describe the energy transfer or transformations for each of the items below.
1. Clapping Your Hands:
Kinetic- sound
2. Dropping Your Pencil:
3. The Toaster:
Electric-Thermal/Heat
4. A Cat Lying in a Sunny Window:
Light-Thermal/heat
5. Lifting a Book Over Your Head:
kinetic-potential
6. The Radio:
Electric-sound
Tell me if correct or not
Answer:
Looks good to me
Explanation:
#2 should probably be turning potential energy to kinetic.
Which of these do not affect fluid friction?
The surface of an object
The viscosity (thickness) of fluid an object is in
The shape of an object
The weight of an object
Draw the graphs for exothermic and endothermic reactions Label: axes, reactants, products, Energy of reaction, heat energy change
Answer:
axes, reactants, products, Energy of reaction, heat energy
Explanation:
axes, reactants, products, Energy of reaction, heat energyaxes, reactants, products, Energy of reaction,grreactantsaphs heat energy
A volleyball that has an initial momentum of
−
1.0
kg
⋅
m
s
−1.0kg⋅
s
m
minus, 1, point, 0, start text, k, g, end text, dot, start fraction, start text, m, end text, divided by, start text, s, end text, end fraction changes direction after a hand hits it with a force of
150
N
150N150, start text, N, end text for
0.01
seconds
0.01seconds0, point, 01, start text, s, e, c, o, n, d, s, end text.
A hand hits a volleyball. An arrow points to the right, in the directio
Answer:
10-
Step-by-Step Explanation:
37. The progressive loss of material from a surface by the mechanical action of a fluid on a surface is called
Answer:
The progressive loss of material from a surface by the mechanical action of a fluid on a surface is called erosion.
An object is projected with speed of 4ms at an angle of 60° to horizontal. Calculate the time of flight of the object. (g=10ms2)
0.8 seconds
Explanation:
time of flight = 2u/g
u=4m/s
g=10
= 8/10
= 0.8 sec
just a trial...not sure!!!
Given :
∅ = 60⁰
u = 4 m/s
g = 10m/s²
to find :
T = ?
Solution :
as per formula,
[tex]t = \frac{2u \: sin \theta}{g} [/tex]
now put the value : [tex]t \: = \frac{2 \times 4 \times sin \: 60}{10} [/tex]
as we know [tex] sin60 \: = \frac{ \sqrt{3} }{2} [/tex]
therefore,
[tex]t \: = \frac{8 \times \frac{ \sqrt{3} }{2} }{10} [/tex]
as we solve this we get,
[tex]t \: = \frac{ 2\sqrt{3} }{5} [/tex]
that's t = 0.69 sec
[tex]\sf\fbox\red{\:I \:hope \:it's \:helpful \:to \:you}[/tex]
Which of the following describes the motion of a block while it is in equilibrium? The block:
A. moves at a constant speed
B. slows down gradually to stop
C. speeds up for a bit, then moves at a constant speed
D. Accelerates constantly
The statement that describes the motion of a block while it is in equilibrium is: The block moves at a constant speed.
EQUILIBRIUM:A state of equilibrium in physics refers to a state of rest or the forces exerted on the object is in a balanced state.
In dynamic equilibrium, the acceleration of a body is zero. This means that the body is moving at a uniform speed.
Therefore, the statement that describes the motion of a block while it is in equilibrium is: The block moves at a constant speed.
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Which one of the following statements concerning a collection of gas molecules at a certain temperature is true?A. The lower the temperature, the greater are the molecular speeds. B. Most of the molecules have the same kinetic energy. C. All molecules possess the same momentum. D. The molecules have a range of kinetic energies. E. All molecules move with the same velocity.
Answer:
D Is true - the velocities (and squared) follow the appropriate statistical curve
The molecules have a range of kinetic energies at a certain temperature. As the temperature increases, their kinetic energy and molecular speed increases.
What is kinetic theory of gases ?Kinetic theory of gases describes the nature of ideal gases and their volume, pressure and kinetic energy. As per this theory the gases are made of tiny particles which have negligible mass compared to that of the container.
Kinetic theory states that the kinetic energy of all gases increases with increase in temperature which is independent of the masses and and at certain temperature all the gases are having same range of kinetic energies.
The velocity of all the gaseous particles increases with increasing in temperature which results in the increase in kinetic energy. Hence, option D is correct.
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Which car is experiencing negative acceleration?
A. a car sitting at a red light
B. a car slowing down as it approaches a red light
C. a car driving in a circle at a constant speed
D. a car changing its speed from 0 km/hr to 10 km/hr
Answer:B
Explanation:
Answer: b
Explanation: b as it slows down and decelerates
What is activated by the sympathetic system?
1. The digestive system
2. The "rest and digest" response
3. O The "fight or flight" response
4. The "breed and feed" response
Answer:
1 the digestive system thats all
Four balls with different masses are dropped from the heights shown. Air resistance may be ignored. Which ball has the greatest average speed?
Answer:
The one falling from the greatest height will have the greatest speed.
h = 1/2 g t^2 time for ball to fall distance h
h2 / h1 = t2^2 / t1^2 dividing equations
h2 / t2^2 = h1 / t1^2
Let v be the average speed (v2 = h2 / t2)
1 / t2 * v2 = 1 / t1 * v1
v2 / v1 = t2 / t1 the one taking the longest to fall has the greater av. speed
Check:
h4 / h1 = t4^2 / t1^2 or
t4 / t1 = (h4 / h1)^1/2
In this case t4 / t1 = (4 / 1)^1/2 = 2 or twice the average speed
t1 = (2 h / g)^1/2 = .2^1/2 = .447 using g = 10
t4 = (2 h / g)^1/2 = .8^1/2 = .894
v1 = 1 / .447 = 2.24 m/s average speed
v4 = 4 / .894 = 4.47 or twice the average speed
A simple machine where an inclined plane is wrapped in a spiral is called a lever.
Answer:
Cool. What’s the Question?
Explanation:
at room tmeperature none of the metals are
What metal is not at room temperature?
Mercury is a metallic chemical element that is an only metal that is not a solid at room temperature.
what is the relationship between work and mechanical advantage
A student removed a wool hat from her head. Her hair stood up from static electricity. What did her hat do to cause this
Answer:
A student removed a wool hat from her head. Her hair stood up from static electricity. What did her hat do to cause this? ... Yes, the motor would run faster because the increased electrical force increases the magnetic force in the motor.
A student removed the wool from her head due to the static charge of electricity, it is caused.
What is charge?A difference in electric charge within, on the surface of, or between two materials results in static electricity. Until it can be expelled through an electrical discharge or current, the charge stays. In contrast to current electricity, which transmits energy by letting an electric charge flow through a conductor or a space, static electricity does not transport energy.
When two surfaces come into contact, wear, and separate from one another when at least a single surfaces has a good resistance to electric current, a static electrostatic attraction can be produced. Because individuals can feel, hear, and even see a spark when the extra charge is neutralized when placed close to a powerful electrical conductor, most people are familiar with static electricity's effects.
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A container holds 192 g of oxygen gas at a pressure of 8.00 atm.
How much heat Q is required to increase the temperature by
145 °C at constant volume?
The quantity of heat (Q) that is required to increase the temperature at constant volume is 18,082.95 Joules.
Given the following data:
Mass of oxygen gas = 192 gPressure = 8.00 atmTemperature = 145°CScientific data:
Ideal gas constant, R = 8.314 J/molKMolar mass of oxygen gas = 32 g/mol.To determine the quantity of heat (Q) that is required to increase the temperature at constant volume:
First of all, we would find the number of moles of oxygen gas.
[tex]Number\;of\;moles = \frac{mass}{molar\;mass}\\\\Number\;of\;moles = \frac{192}{32}[/tex]
Number of moles = 6 moles.
At constant volume, the heat capacity for a diatomic gas is given by:
[tex]C_v = \frac{5}{2} R\\\\C_v =\frac{5}{2} \times 8.314[/tex]
Heat capacity = 20.785 J/molK.
At constant volume, the quantity of heat (Q) is given by this formula:
[tex]Q = nC_v \Delta T\\\\Q=6 \times 20.785 \times 145[/tex]
Quantity of heat (Q) = 18,082.95 Joules
Note: [tex]\Delta T[/tex] = 145°C = 145 K (since the difference is the same).
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Michelle recently started selling her invention: A bed that looks like it floats in mid-air. The bed is actually suspended by magnetic forces. Michelle is a(n)
Answer:
Explanation:
designer
illusionist
engineer
entrepreneur
salesperson
human
inventor
Explain why the temperature is not changing at X
Answer:
The temperature is constant at 'X'. No increase or decrease. Would be same answer if there were a 'X' at temperature 'D'.
Slope of graph is zero so no change in the temperature.
What is temperature?
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer.
Given graph of temperature and time, at position x there in no change in temperature with time so temperature is not changing.
Slope of graph is zero so no change in the temperature.
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Observe and compare the forces acting on the turtle and the cat.
a turtle and a cat on the ground looking at each other and not moving
Public Domain
The forces are balanced on both animals because they are not moving.
The forces are unbalanced on both animals because they are not moving.
The forces are balanced on the turtle but unbalanced on the cat because it is heavier.
The forces are balanced on the cat but unbalanced on the turtle because the cat is larger.
Answer:
The forces are balanced on both animals because they are not moving
More importantly than not moving is not accelerating.
Explanation:
Answer: A! the animals are doing the same thing, the force is applied to both also there not moving
Explanation:
A body is thrown up into the air takes a time of 4s to reach the height. What is the velocity with which the body was thrown up.(g=10ms2)
Answer:
40m/s
Explanation:
V= u + at
v= 0
a= -10
t= 4
0= u -40
u= 40m/s
just trial!!!!!!!
please help
Two masses m1 and m2, are a distance R apart and mq exerts a gravitational force F on m2. What is the gravitational force is the gravitational force on M1?
Answer:
F
Explanation:
for every action there exists an equal and opposite reaction. The force acting on the two masses is identical in magnitude, but opposite in direction.
what is dispersion of light?
Answer:
[tex] \huge \bold \blue{ \underline{ answer}}[/tex]
The splitting up of light into its constituent colours while passing from one medium to the other is called dispersion.
Is this right for the second one
Answer:
Yes.
Explanation:
There is no movement in magnetic, chemical, electrostatic, or nuclear (potential) energy. The other options for that question can't be right. Mechanical energy is a form of kinetic, so B cannot be true. Thermal energy is also kinetic, which makes C and D incorrect as well.
just this last one!!
A car slams on its brakes creating an acceleration of -4.7 m/s^2. It comes to rest after traveling a distance of 235 m. What was its velocity before it began to accelerate?
Answer:
[tex]47 \ \frac{m}{s}[/tex]
Explanation:
s = displacement (m)
u = initial velocity [tex](\frac{m}{s})[/tex]
v = final velocity [tex](\frac{m}{s})[/tex]
a = acceleration [tex](\frac{m}{s^{2} })[/tex]
t = time (s)
s = 235
a = -4.7
v = 0
v² = u² + 2as
(0)² = u² + 2(-4.7)(235)
u² - 2209 = 0
u² = 2209
u = 47
Answer:
[tex]\boxed {\boxed {\sf 47 \ m/s}}[/tex]
Explanation:
We are asked to find the initial velocity of the car before it began to accelerate.
We are given the acceleration, distance, and final velocity, so we will use the following kinematic equation:
[tex]{v_f}^2 = {v_i}^2 + 2ad[/tex]
The car's acceleration is -4.7 meters per second square. It traveled a distance of 235 meters. It came to rest, or a final velocity of 0 meters per second.
a= -4.7 m/s²d= 235 m [tex]v_f[/tex]= 0 m/sSubstitute the values into the formula.
[tex](0 \ m/s)^2 = {v_i}^2 + 2 (-4.7 \ m/s^2)(235 \ m)[/tex]
[tex]0 = {v_i}^2 + 2 (-4.7 \ m/s^2)(235 \ m)[/tex]
Multiply the numbers in parentheses.
[tex]0= {v_i}^2 + (-2209 \ m^2 / s^2)[/tex]
Add -2209 to both sides of the equation.
[tex]0+ 2209 \ m^2 /s^2 = {v_i}^2+ ( -2209 \ m^2 /s^2 )+ 2209 \ m^2 /s^2[/tex]
[tex]2209 \ m^2 /s^2 = {v_i}^2[/tex]
Take the square root of both sides.
[tex]\sqrt {2209 \ m^2 /s^2} = \sqrt {{v_i}^2[/tex]
[tex]\sqrt {2209 \ m^2 /s^2} = v_i[/tex]
[tex]47 \ m/s = v_i[/tex]
The inital velocity of the car was 47 meters per second.
Section 1: Basic Energy Relationships
1. Click/tap the Start button and observe the motion. View the bar
charts and the velocity value as the coaster car moves. Complete
the following paragraph by entering total mechanical energy
(ME), kinetic energy (KE), and potential energy (PE). The
labeled locations refer to the graphic at the right.
As the coaster car rolls down the track from A to E, the
________ values decrease and the _______ value
increase and the ________ values remain constant. The
_______ is greatest at point A and smallest at point E.
However, the _______ is smallest at point A and largest
at point E.
Section 2: Hill Design
2. Click/tap on the Bumps tab at the top of the
Interactive. Then drag the grey circles to modify the
track so that it looks like the track design at the right.
Pay attention to the background grid to help with the
design. Note that Dot G is at the same height as Dot E;
make sure that the same is true of your final design.
3. Run the simulation. Does the coaster car travel as high
as point H? ___________ Give an explanation for why
it does or doesn't reach point H.
As the coaster car rolls down the track from A to E, the potential energy values decrease and the kinetic energy value increase and the total mechanical energy values remain constant. The potential energy is greatest at point A and smallest at point E. However, the kinetic energy is smallest at point A and largest at point E.
According the principle of conservation of mechanical energy, as the potential energy decreases, the kinetic energy increases.
[tex]P.E + K.E = M.A[/tex]
At point A, the coater has maximum potential energy.
At point E, the coaster has maximum kinetic energy.
We can fill the blanks as follows;
As the coaster car rolls down the track from A to E, the potential energy values decrease and the kinetic energy value increase and the total mechanical energy values remain constant. The potential energy is greatest at point A and smallest at point E. However, the kinetic energy is smallest at point A and largest at point E.
Based on the principle of conservation of mechanical energy, if the second simulation occurs at the same condition as the first, the height reached by coaster will be same.
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Which sentence states Newton's second law?
Answer:
Force is equal to the change in momentum per change in time.
Explanation:
That situation is described by Newton's Second Law of Motion. According to NASA, this law states, "Force is equal to the change in momentum per change in time. For a constant mass, force equals mass times acceleration." This is written in mathematical form as Force = mass.