Answer:
310 s
Explanation: t = w ÷ p = 4.7 x 10^6J ÷ 15,000w
t = 310 s
A rope hangs over a frictionless pulley attached to the ceiling. A weight is attached to each end of the rope. One end of the rope has 10 kg weight, the other has a 20 kg weight. The system consists of: the pulley, rope, the two weights, and Earth. Initially the weights are suspended at the same height above the ground. When the weights are released, the heavier weight falls, lifting up the lighter weight. Movement stops when the heavier weight reaches the floor.
Which choice best describes the changes in kinetic and potential energy?
At the moment when the movement stops, the lighter object has zero kinetic energy and maximum potential energy while the heavier object has maximum kinetic energy and zero potential energy.
Conservation of mechanical energy
The principle of conservation of mechanical energy states that the total mechanical energy of isolated system is always constant.
M.A = P.E + K.E
where;
P.E is the potential energyK.E is the kinetic energyTherefore, at the moment when the movement stops, the lighter object has zero kinetic energy and maximum potential energy while the heavier object has maximum kinetic energy and zero potential energy.
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A young child holds a string attached to a balloon. What is the reaction force to the child pulling down on the string?
A. The child giggles with laughter.
B. The string pulls up on the child.
C. Gravity pulls the balloon down.
D. The balloon moves.
Answer:
The Answer Choice is C , Gravity Pulls the Balloon down
Answer:
B. may be
Explanation:
Gravity is greater than the string
pulling force.
SORRY IF MY ANSWER NEED ANY.
22. True or False... The original unstable isotope is the daughter isotope.
Answer:
false
Explanation:
A drag racer accelerates uniformly over a course 400m long. Determine the car's acceleration if it reaches a top speed of 120 m/s. Assume that the car starts from rest.
Apply third equation of kinematics
[tex]\\ \rm\hookrightarrow v^2-u^2=2as[/tex]
Isolate the equation for a
[tex]\\ \rm\hookrightarrow a=\dfrac{v^2-u^2}{2s}[/tex]
[tex]\\ \rm\hookrightarrow a=\dfrac{v^2}{2s}[/tex]
[tex]\\ \rm\hookrightarrow a=120^2/800[/tex]
[tex]\\ \rm\hookrightarrow a=18m/s^2[/tex]
Donna jogs to work, a distance of 3 km, at an
average speed of 8 km/h. If she leaves home at
8:00am, at what time will she arrive at work?
explanation
we take distance covered divided by speed
=3/8
=0.375h
=22min
time =8.00+0.22
=8.22am
1 point
Answer in True/False. A) The motor speed is less than wheel speed. B) The output power of the motor is positive during hill climbing. C) The wheel torque is more than motor torque
For the following statements
A) The motor speed is less than wheel speed.
B) The output power of the motor is positive during hill climbing.
C) The wheel torque is more than motor torque
These assertions are given respectively as
falsetruefalseWhat are speed, power, and Torque?Speed: defined as the ratio of operation with respect to distance and time
Power: defined as the ability to work
Torque: This is the speed of a rotating object
Generally, the equation for Speed, Power, Torque is mathematically given as
V=m/s
P=w/t
T=rfsin\theta
In conclusion
For a moving car, the wheels speed is in equilibrium with the motor speed Hence false
The output power during a hill climb is is positive cause work is been done
Hence true
The wheel torque also is in equilibrium with the motor Torque Hence false
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Angular Quantities: When a fan is turned off, its angular speed decreases from 10 rad/s to 6.3 rad/s in 5.0 s. What is the magnitude of the average angular acceleration of the fan
Answer:
angular acceleration = change in angular speed / change in time
angular acceleration = 10 rad/s - 6.3 rad/s / 5s
angular acceleration = 3.7 rad/s / 5s
angular acceleration = 0.74 rad/s^2
A 10-kg object weighs nearly 100 N on Earth. Would it weigh more or less on the Mars? Wouldits mass will be different on the Moon?
Answer:
less
Explanation:
weight = mass * acceleration due to gravity----(1)
the acceleration due to gravity on Mars is less than on earth. From equation (1 )we can say that weight in Mars is less than earth.
kon'nichiwa~
please help me with this question!!
Let's check the relationship
[tex]\\ \rm\hookrightarrow g=\dfrac{GM}{r^2}[/tex]
[tex]\\ \rm\hookrightarrow g\propto G[/tex]
So
Raindrops will fall faster . .Also walking on ground would become more difficult as g increases.Option C is wrong by now .Let's check D once
[tex]\\ \rm\hookrightarrow T\propto \dfrac{1}{\sqrt{g}}[/tex]
So time period of simple pendulum would decrease.How does forces affect the acceleration of a body
example of what happens to particles when their kinetic energy decreases?
Explanation:
When we decrease the temperature, less heat energy is supplied to the atoms, and so their average kinetic energy decreases. When they enter a phase transition, such as freezing from a liquid to a solid, the temperature is not decreasing or increasing, and stays constantAnswer:
when the kinetic energy of a particle decreases, according to me that body must have been freeze, like water particles or intermolecular force which losses when heated (gains more kinetic energy) and when freeze losses kinetic energy.
A source charge generates an electric field of 1236 N/C at a distance of 4 m. What is the magnitude of the source charge? (Use k=) 2. 2 µC 680 µC 2. 2 C 680 C.
Hi there!
The equation for the electric field of a point charge is given by:
[tex]E = \frac{kq}{r^2}[/tex]
E = Electric Field (N/C)
k = Coulomb's Constant
r = distance (m)
We can rearrange to solve for 'q':'
[tex]q^2 = \frac{Er^2}{k}\\\\q = \sqrt{\frac{Er^2}{k}}[/tex]
Plug in the values and solve:
[tex]q = \sqrt{\frac{(1236)(4^2)}{(8.99*10^9)}} = \boxed{0.00148 C}[/tex]
During a lab investigation, students added four 50 g masses to two boxes and arranged the boxes so that they were motionless on a pulley, as shown in the diagram. The students then followed the procedure described in the box. The students recorded their observations after each procedure and reset the pulley system to the original conditions. During which procedures did students observe an unbalanced upward force on Box 1? A) Procedures 1, 2, and 3 B) Procedures 4 and 5 C) Procedures 3 and 4 D) Procedures 3 and 4.
When the resultant force is not equal to zero termed an unbalanced force. By procedures 4 and 5 students observe an unbalanced upward force on Box 1. Hence option 1 is right for the problem.
What is an unbalanced force?The forces operating on a body are known as unbalanced forces when the resulting force exerted on it is not equal to zero.
Unbalanced forces acting on the body, causing it to modify its state of motion. To further grasp the nature of imbalanced forces.
The following reasons by which we can understand the unbalanced force caused by the box.
Due to these two reasons, books will move up.
By adding another mass to box 2. The box becomes lighter. As the box becomes lighter the gravity force acting on the box will be less due to which the box easily can move up.
By removing the two masses from box 1. Due to which other become heavier other becomes heavier pulling it down causing box 1 one to go up.
Hence by procedures 4 and 5 students observe an unbalanced upward force on Box 1. Hence option 1 is right for the problem.
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Why are some solutions better conductors of electricity.
Answer:
Strong electrolytes have a better tendency to supply ions to the aqueous solution than weak electrolytes.
Explanation:
The Earth rotates 1 time every 24 hours….
A. How many RPM’s is this?
B. What is the velocity of a person standing on the surface of the Earth 6,378,000 m from the center?
Answer:
A. 0.000694 RPM
B. 463 m/s
Explanation:
What type of radiation can be stopped by a approximately 5 cm of air.
Determine an expression for the charge on the capacitor as a function of time, q(t), in terms of parameters given in the original problem statement.
The expression for the charge on the capacitor as a function of time is [tex]q(t) = q_0e^{-\frac{t}{RC} }[/tex].
Charge on capacitor as a function of time
Q = It
lnQ = -t/RC
ln(q - q₀) = -t/RC
[tex]q-q_o = e^{-\frac{t}{RC} }\\\\q = q_0e^{-\frac{t}{RC} }\\\\q(t) = q_0e^{-\frac{t}{RC} }[/tex]
where;
q is the charge R is resistanceC is capacitancet is timeThus, the expression for the charge on the capacitor as a function of time is [tex]q(t) = q_0e^{-\frac{t}{RC} }[/tex].
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E) Would you expect the temperature of the water to continue rising above 20°C? Explain your answer.
Answer:
No, when water converts to steam on heating, the temperature remains constant at the boiling point and the heat supplied to the water is used for the vaporisation of water, rather than increasing the temperature of water.
This energy used for the vaporisation is termed as the latent heat of vaporisation.
You’ll find similar observations if you try heating ice - the temperature remains at 0∘ Celsius. Here, it’s the latent heat of fusion.
You are part of a police unit that has found a powder in a suspect's home. You think it might be a new drug called XYZ. XYZ is an ionic compound that dissolves in water. However, what you think might be a drug may just be salt. Unfortunately there seems to be iron fillings and sand mixed in with the white powder. Your job is to isolate the white powder before sending it to the police lab to be tested to determine if it is salt or XYZ. Give step by step directions on exactly how you will separate your mixture of white powder, iron fillings, and sand.
Answer:
a magnet and sifter
Explanation:
a magnet will get all the iron filling and the sifter will separate the powder and sand
During a baseball game, a batter hits a high pop-up. if the ball remains in the air for a total of 6.0 s, how high does it rise? ( Assume Accel. = 10 m/s^2 )
Apply second equation of kinematics
[tex]\\ \rm\hookrightarrow s=ut+\dfrac{1}{2}gt^2[/tex]
[tex]\\ \rm\hookrightarrow s=1/2(10)(3)^2[/tex]
[tex]\\ \rm\hookrightarrow s=5(9)[/tex]
[tex]\\ \rm\hookrightarrow s=45m[/tex]
It rises 45m
Philip was diagnosed with __________ vestibular disorder, which is a dysfunction of the nervous system that processes balance. A. Upper B. Peripheral C. Lower D. Central.
Answer:
D. Central
Explanation:
Post WWII Germany was divided into four zones with the Americans occupying one zone and all of the following countries occupying a zone EXCEPT:
a. USSR
c. France
b. Italy
d. England
Answer:
b. Italy
Explanation:
Italy had sided with germany and lost in world war 2
After the Potsdam conference, Germany was divided into four occupied zones: Great Britain in the northwest, France in the southwest, the United States in the south and the Soviet Union in the east.
europeuncedu
When two objects of unequal masses collide with no other external forces, what happens to the momentum within the system?
1) A 2-kg object moving at 10 m/s has a 4-N force applied to it. Can you predict how the force will affect the object?
es
A) yes, it will slow it down at a rate of 2 m/s?
B) yes, it will speed it up at a rate of 2 m/s
yes, it will speed it up at a rate of 4 m/s?
D) It cannot be determined without more information,
아
Hint
Regular Calc
Graphing Calc
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Answer:D) It cannot be determined without more information,
Explanation:
If the scaled-up man now stands on one leg, what fraction of the tensile strength is the stress on the femur?.
The new cross sectional area and tensile stress is mathematically given as
A=4.8*10^{-4}m^2
X=14:100
Cross sectional area and stress on the femurQuestion Parameters:
To see why this must be so, recall, that the stress on the femur for a man standing on one leg is 1.4%
we scale this man up by a factor of 10 in all dimensions
that a 70 kg person has a femur with a cross-section area
a)
Generally the New cross sectional area is mathematically given as
100A=100*4.8*10^{-4}
A=4.8*10^{-4}m^2
b)
From the initial statement we see that the fraction of the tensile strength is the stress on the femur and will be
[tex]X=\frac{14}{100}[/tex]
X=14$
X=14:100
For more information on fraction
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Complete Question
Larger animals have sturdier bones than smaller animals. A mouse's skeleton is only a few percent of its body weight, compared to 16% for an elephant. To see why this must be so, recall, that the stress on the femur for a man standing on one leg is 1.4% of the bone's tensile strength. Suppose we scale this man up by a factor of 10 in all dimensions, keeping the same body proportions. (Assume that a 70 kg person has a femur with a cross-section area (of the cortical bone) of 4.8 x 10-4m², a typical value.)
Part A
Both the inside and outside diameter of the femur, the region of cortical bone, will increase by a factor of 10. What will be the new cross-section area? Express your answer using two significant figures.
Part B
If the scaled-up man now stands on one leg, what fraction of the tensile strength is the stress on the femur?
Electric fields are usually created when _____ are transferred between objects? *.
Answer:
electrons
Explanation:
Electric fields are usually created when electrons are transferred between objects?
Approximately how much charge must a bee transfer to the flower to create a 30 V potential difference
7
Analisa wants to save her money in a place where she can have access to it anytime in case of an emergency. Which option BEST fits Analisa's
wishes?
OA.
CD
ОВ.
savings account
Ос.
bond
OD. stocks
Savings account is where she can have access to her money anytime in case of an emergency.
What is a Savings account?This is a type of account run by a financial institution which yields interests on deposits made.
This type of account usually comes with features in which the money can be withdrawn via an ATM card or by visiting the bank to collect it. This therefore makes it the most appropriate choice for Analisa.
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A force of 2000N pulls a load at an angle of 60degrees with the horizontal. if the weight of the object is 3000N, Calculate the coefficient of static friction.
Answer:
If one assumes that F will just start the object to move:
F = μ Wa cos θ where θ is the angle of the applied force
and Wa is the apparent weight of the object
μ = F / (Wa cos θ)
Note that Wa = W - F sin θ true weight less component of applied force
Wa = 3000 - 2000 sin 60 = 1268 N
μ = 2000 / (1/2 * 1268) = 3.15 (seems to be very large, usually < 1)
Any sound with a frequency that is too high for humans to hear is called.
Answer:ultrasound
Explanation:
