Answer:
A theory not only explains known facts; it also allows scientists to make predictions of what they should observe if a theory is true. Scientific theories are testable. New evidence should be compatible with a theory. If it isn't, the theory is refined or rejected.
Explanation:
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A girl of mass m1=60.0 kilograms springs from a trampoline with an initial upward velocity of vi=8.00 meters per second. At height h=2.00 meters above the trampoline, the girl grabs a box of mass m2=15.0 kilograms. (Figure 1)
For this problem, use g=9.80 meters per second per second for the magnitude of the acceleration due to gravity.
What is the speed vbefore of the girl immediately before she grabs the box?
Express your answer numerically in meters per second.
What is the speed vafter of the girl immediately after she grabs the box?
Express your answer numerically in meters per second.
What is the maximum height hmax that the girl (with box) reaches? Measure hmax with respect to the top of the trampoline.
The conservation of momentum and energy allows to shorten the results for the movement of the girl on the trampoline holding the box are:
a) the girl's speed is v = 4.98 m / s
b) The speed of the girl + box system is: v_f = 0.996 m / s
c) the maximum height is: y = 2.05 m
Kinematics studies the movement of bodies, looking for relationships between the position, velocity and acceleration of bodies.
The momentum is defined by the product of mass and the velocity, when a system is isolated the momentum is conserved.
The mechanical energy is the sum of the kinetic energy plus the potential energies, when there is no friction in the system the mechanical energy is conserved.
Let's solve this exercise in parts:
a) Let's use kinematics to find the speed of the girl before she grabs the box
v² = v₀² - 2 g y₁
v² = 8² - 2 9.8 2.00
v = R 24.8 = 4.98 m / s
b) Let's use momentum conservation for when the speed of the girl and the box together. Let's write the moment in two moments.
Initial instant. Just before you grab the box.
p₀ = M v + 0
Final moment. Right after taking the box
[tex]p_f[/tex] = (m + M) [tex]v_f[/tex]
In system this form by the girl and the box therefore it is an isolated system and the momentum is conserved.
[tex]p_o = p_f[/tex]
mv = (m + M) [tex]v_f[/tex]
[tex]v_f = \frac{m}{m+M} \ v[/tex]
Let's calculate
[tex]v_f = \frac{15}{15+ 60} \ 4.98[/tex]
[tex]v_f[/tex] = 0.996 m / s
c) Now we use conservation of energy after the girl has the box.
Starting point. When the girl has the box
Em₀ = K + U
Em₀ = ½ (m + M) v² + (m + M) g y₁
Final point. At the highest point of the trajectory
[tex]Em_f[/tex] = U
[tex]Em_f[/tex] = (m + M) g y₁
As there is no friction, the energy is conserved.
[tex]Em_o = Em_f[/tex]
½ (m + M) v² + (m + M) g y₁ = (m + M) g y
y = [tex]\frac{v^2}{2g} + y_1[/tex]
Let's calculate
y = [tex]\frac{0.996^2}{2 \ 9.8} + 2.0[/tex]
y = 2.05 m
In conclusion using the conservation of momentum and energy we can shorten the results for the movement of the girl on the trampoline holding the box are:
a) the girl's speed is v = 4.98 m / s
b) The speed of the girl + box system is: v_f = 0.996 m / s
c) the maximum height is: y = 2.05 m
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Answer:
Vbefore = 4.98 m/s
Vafter = 3.98 m/s
Hmax = 2.81 m
Which force, in real life, will have the least effect on a bowling ball rolling down a lane toward bowling pins?
A) magnetism
B) air resistance
C) gravity
D) friction
Answer:
Its Friction
Explanation:
the pins are not floating and they are not a magnet and not involved with air
The force, in real life, that will have the least effect on a bowling ball rolling down a lane toward bowling pins is magnetism. The correct option is A.
What is magnetism?Magnetism is basically the force which indeed magnets exert when they attract or even repel one another. The movement of electric charges resulting in magnetism.
Every substance is composed of tiny units referred to as atoms. Each atom contains electrons, which are charged particles.
To increase stability, the pins themselves have a low center of gravity. Because they are spherical in shape, they can roll and strike other pins in a variety of directions.
The force acting on the bowling ball is friction and air resistance. The friction force is equal to the friction coefficient multiplied by the normal force, and thus mass times acceleration.
Thus, the correct option is A.
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Am object of mass in a circular path of radius 100metres with the speed of 10metres/second.calculate the acceleration towards the center
Answer:
is 6
Explanation:
h
If I have an object that starts from rest and reaches a velocity of 25m/s over a distance of 11m what is the acceleration of the object
28.4m/s
28m/s
28.4m/s^2
28m/s^2
Answer:
Here is something that may help you!!
Explanation:
I found it in a cite (not that I'm plagiarizing, or anything).
 what is the difference between repelling and attracting
Answer:
Attracting means pulling toward you and repelling means pushing away
Explanation:
Answer: Repelling is when something will not connect with another object. The force will cause a repel between the two objects. Attracting is when something is attracted or being pulled to another object.
Explanation: Hope this helps!
Acceleration of a car that speeds from 4.3 m/s to 12.9 m/s in 2 seconds
Explanation:
let v1 = 4.3 m/s
v2 = 12.9 m/s
t = 2 seconds
v2 = v1 + at
12.9 = 4.3 + a×2
2a = 12.9 - 4.3 = 8.6
a = 8.6/2
a = 4.3 m/s^2
Alex is x years old . June is 7years older than Alex . their total combined ages is 29 years . find June,s age . show all work algebraically
Answer:
18 yearsExplanation:
Given,
Let Alex be = x years
Then June will be = (7 + x) years
We know that,
Their total combined age is 29 years
Therefore,
By the problem,
=> x + (7 + x) = 29
=> 2x = 29 - 7
=> 2x = 22
=> x = 22 ÷ 2
=> x = 11
So,
Required age of June is = (7 + x) years
= (7 + 11) years
= 18 years (Ans)
Which scientist is credited with having the greatest contribution to early microscopy and was the first to observe and describe single-celled organisms?
Answer:
Antonie van Leeuwenhoek
Explanation:
When a capacitor has a charge of magnitude 80 μC on each plate the potential difference across the plates is 16 V. How much energy is stored in this capacitor when the potential difference across its plates is 42 V?
Answer:
4.410 mJ
Explanation:
The capacitance is ...
C = Q/V
C = (80 μC)/(16 V) = 5 μF . . . . . variable C = capacitance; unit C = coulombs
Then the energy stored at 42 V is ...
E = 1/2CV² = (1/2)(5 μF)(42 V)² = 4.410 mJ
The 5 μF capacitor stores about 4.41 millijoules at 42 V.
A meter stick is attached to one end of a rigid rod with negligible mass of length l = 0.302 m. The other end of the light rod is suspended from a pivot point, as shown in the figure below. The entire system is pulled to a small angle and released from rest. It then begins to oscillate. A meter stick hung from a rod of length l. The rod is attached to the ceiling. The rod and meter stick extend downward in a straight line making a small angle with the vertical. (a) What is the period of oscillation of the system (in s)? (Round your answer to at least three decimal places.)
The period of oscillation of the system nearest to three decimal places
= 1.092 seconds
The period of an oscillation occurring in a system is the time taken to complete one cycle.
The formula that is used to calculate the period of oscillation (T) is
= 2π√[tex]\frac{l}{g}[/tex]
But,
π = 3.14159 (constant)
g= 10m/s² (acceleration due to gravity)
l = 0.302 m
Therefore T = 2 × 3.14159 × √[tex]\frac{0.302}{10}[/tex]
= 6.28318 x √0.0302
= 6.28318 x 0.17378
= 1.09189s
= 1.092 seconds ( to the nearest three decimal places)
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What is non examples of enlarged
reduction
deflation
these are examples of the opposite of enlarged to make something smaller is really the key thing here
Geologists collect and study hand samples because they can be used to understand
which
Geologists use a lot of tools to aid their studies. Some of the most common tools used are compasses, rock hammers, hand lenses, and field books.
A bicyclist travels 30 km in 2 hours east. Calculate its velocity?
Answer:
Its velocity would be
15 km per hour
or
0.00416667 per second
A mystery fluid has a density of 6.45kg/m^3 . If 2.34 kg are put into a container, what is the volume of the sample?
Answer:
0.36 m³Explanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\[/tex]
From the question
mass = 2.34 kg
density = 6.45 kg/m³
We have
[tex]volume = \frac{2.34}{6.45} \\ = 0.36279...[/tex]
We have the final answer as
0.36 m³Hope this helps you
You have a weight of W on earth. Find your new weight, in terms of W, if you go to a planet with a radius 3 times more a than Earth and a mass 2 times more than Earth.
A 6W
B 2W/3
C 2W/9
D 18W
Hi there!
We know that the acceleration due to gravity is given by:
[tex]g = \frac{Gm_o}{r^2}[/tex]
We can plug in the given values assuming that the above equation represents the earth's gravitational acceleration:
[tex]g_{planet} = \frac{G(2m)}{(3r)^2} = \frac{2}{9}(\frac{Gm}{r})[/tex]
Since the acceleration due to gravity of this other planet is 2/9th of the acceleration due to gravity on earth, the weight:
W = mg, will also be 2/9ths of that of earth. The correct answer is C.
Câu 9. Một dây dẫn đồng chất, tiết diện đều 20mm2 có dòng điện không đổi 12A đi qua. Tính trị trung bình mật độ dòng điện j ?
Answer:
Sorry I can't understand you
If you do 72 J of work in 1.2 seconds, how much power is produced
Answer:
Explanation:
Power is the rate of doing work
P = 72 / 1.2 = 60 Watts
1.25 is closer to 1.04 or not ?
plz heelp plz
Answer:
No, it is closer to 1.30
Explanation:
A soccer ball is kicked from the roof of a building with a height of 45.0m, near the surface of the Earth, with an initial velocity vi=14.2m/s. The ball exists the surface of the roof moving horizontally.
A) How long is the ball in the air?
B)How far away from the base of the building does the ball land?
C) How fast is the ball moving just before it strikes the ground?
D) At what angle does the ball strike the ground? This angle is measured with respect to the horizontal direction.
Answer:
its c
Explanation:
Which of the following scenarios would have the MOST friction force between the object and the surface?
A. a 7 kilogram bicycle with rubber tires on concrete
B. a 7 kilogram bicycle with rubber tires on ice
C. a 0.25 kilogram toy car with rubber tires on ice
D. a 0.25 kilogram toy car with rubber tires on concrete
A student made the table to showing how different objects transform electrical energy. Which statement best explains why the table is incorrect?
Item Transformed Energy
Radio Electrical → Sound
Lamp Electrical → Light
Doorbell Electrical → Motion
Iron Electrical → Heat
The doorbell transforms electrical energy into sound.
The iron transforms electrical energy into light.
The lamp transforms electrical energy into sound.
The radio transforms electrical energy into heat.
Answer:
I think it's ,The radio transforms electrical energy into heat is incorrect
Explanation:
radio don't transforms electrical energy into heat.
A Scooter has a mass of 250 kg. A constant force is exerted on it for 6.0 s. During the time the force is exerted, the scooter increases its speed from 6.00 m/s to 280 m/s. What is the magnitude of the force exerted on the scooter
Answer:
917 N
Explanation:
917 N, this is your answer!!
Glad to help.
A certain laser outputs pure blue light (photon energy 3.1 eV) with power 650 milliwatts (0.65 watts). How many photons per second does this laser emit
The number of photons per second emitted by the laser is [tex]7.64 \times 10^{-19} \ photons /s[/tex].
The given parameters:
energy of the photon, E = 3.1 eVpower of the laser, P = 650 mWThe number of photons per second emitted by the laser is calculated as follows;
[tex]n(P \times t ) = E[/tex]
where;
n is the number of photons1 ev = 1.602 x 10⁻¹⁹ J[tex]n = \frac{E}{P\times t} \\\\n = \frac{3.1 \times 1.602 \times 10^{-19}}{0.65 \times t} \\\\n = 7.64 \times 10^{-19} \ photons/s[/tex]
Thus, the number of photons per second emitted by the laser is [tex]7.64 \times 10^{-19} \ photons /s[/tex].
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A proton is released in a uniform electric field and it experiences an electric force of 2.18x10^-14N toward south .What are the magnitude and direction of the electric field
Answer:
F = E q
E = 2.18E-14 / 1.6E-19 = 1.36E5 N/C
The direction of the field will be the same as force on the proton - southerly
When an elastic object is changed from its original shape:
A:Energy is released
B:Work is done
C:It is ruined
D:It makes a twanging sound
Answer:
deformation : elastic deformation is reversed when the force is removed. inelastic deformation is not fully reversed when the force is removed – there is a permanent change in shape.
Explanation:
tysm
Can someone help me .. please I don’t understand.
An object is moving due north at 31m/s. Does this tell you the speed of the velocity of the object or both?
Answer:
speed
Explanation:
its the speed
because the formula for deriving speed is distance/time
the unit for distance is metre
the unit for time is seconds
so speed is metre/seconds
so speed us m/s.
Explain the difference in how a concave lens and a convex lens affect an object's appearance.
Answer: Varies
Explanation: Concave lens curve inward while convex lens are outward.
Answer:
CONCAVE LENS:
concave lens is thinner in the middle and thicker at the edges. it is also called diverging lens.image formed is virtual and smaller than the object. it's focal length is always negative. it is used for the correction of problem of short sight. Appear smaller and farther. Used to Correct myopia.Curves inward.CONVEX LENS:
convex lens is thicker in the middle and thinner at the edges. it is aso called converging lens.image formed is real and inverted. it's focal length is always positive. used for the correction of problem of long sight. Appear closer and larger. Used to Correct hyperopia.Curves outward.Explanation:
Colette launches an air rocket in the upward, positive direction. It launches with an initial velocity of 25.5 m/s. It accelerates in the downward, negative direction at a rate of 9.81 m/s2. After 3.5 seconds, what is the magnitude of the rocket's displacement?
Answer:
Give me some hint please
What on earth is equal to 9.8m/s/s
Answer:
Acceleration due to gravity
