5) Choose the best revision of the following statement: "All the isotopes of a particular element decay radioactively by
emitting electrons."
A. All the isotopes of a particular element are stable and do not decay.
B. Some isotopes are stable and others are unstable. Unstable isotopes decay by emitting various subatomic
particles and radiation
C. Some isotopes are stable and others are unstable. Unstable isotopes decay by emitting protons or
electrons.
D. The statement is correct as it is currently written.
Answer:
B. some isotopes are stable and others are unstable. unstable isotopes decay by emitting various subatomic particles and radiation.
Explanation:
test gave me the answer so yeah :/ XD
A volleyball experiences 494 Ns of impulse over a time period of 7 seconds. What was the magnitude of the force that acted on the volleyball during this time period?
Answer:
70.6N
Explanation:
Given parameters:
Impulse = 494Ns
Time = 7s
Unknown:
Force applied = ?
Solution:
To solve this problem, we use the formula of impulse;
Impulse = Force x time
Now insert the parameters and solve;
494 = Force x 7
Force = [tex]\frac{494}{7}[/tex]
Force = 70.6N
A car with a mass of 2,000 kg travels at 20 m/s. Which one has the greatest impulse?
Answer:2000kg
Explanation:
Convert it
What is the current in a 160V circuit if the resistance is 200?
What must a scientist do in order to develop a testable hypothesis?
Answer:
Explanation:
Ask a question that can be answered by making observations.
Answer: (APE X) Determine whether experimental observations can provide evidence to support a conclusion
Explanation:
A metallic ring of mass 1 kg has moment of inertia 1 kg m² when rotating about one of its diameters. It is molten and
remoulded into a thin uniform disc of the same radius. How much will its moment of inertia be, when rotated about its own
axis.
Answer:
The moment of inertia of disc about own axis is 1 kg-m².
Explanation:
Given that,
Mass of ring m= 1 kg
Moment of inertia of ring at diameter [tex](I_{r})_{d}=1\ kg\ m^{2}[/tex]
The radius of metallic ring and uniform disc both are equal.
So, [tex]R_{r}=R_{d}[/tex]
We need to calculate the value of radius of ring and disc
Using theorem of perpendicular axes
[tex](I_{r})_{c}=2\times (I_{r})_{d}[/tex]
Put the value into the formula
[tex](I_{r})_{c}=2\times1[/tex]
[tex](I_{r})_{c}=2\ kg\ m^2[/tex]
Put the value of moment of inertia
[tex]MR_{r}^2=2[/tex]
[tex]R_{r}^2=\dfrac{2}{M}[/tex]
Put the value of M
[tex]R_{r}^2=\dfrac{2}{1}[/tex]
So, [tex]R_{r}^2=R_{d}^2=2\ m[/tex]
We need to calculate the moment of inertia of disc about own axis
Using formula of moment of inertia
[tex]I_{d}=\dfrac{1}{2}MR_{d}^2[/tex]
Put the value into the formula
[tex]I_{d}=\dfrac{1}{2}\times1\times2[/tex]
[tex]I_{d}=1\ kg\ m^2[/tex]
Hence, The moment of inertia of disc about own axis is 1 kg-m².
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Answer:
ok followed!
Explanation:
A 2 kg block is sitting motionless on a ramp at 24° with the horizontal. What is the force of friction on the block that resists its motion?
Answer:
7.97 N
Explanation:
[tex]f = m g sin(\alpha) = 2 * 9.8 * sin(24) = 7.97 N[/tex]
the maximum displacement of an oscillatory motion is A=0.49m. determine the position x at which the kinetic energy of the particle is half it's elastic potential energy? (if K.E = U/2 __ x = ?)
Answer:0.4 m
Explanation:
Given
Maximum displacement A=0.49
The sum of kinetic and elastic potential energy is [tex]\frac{1}{2}kA^2[/tex]
where k=spring constant
U+K.E.=[tex]\frac{1}{2}kA^2[/tex]
when K.E.=U/2
K.E.=kinetic energy
U=Elastic potential Energy
[tex]\rightarrow \ U+\frac{U}{2}=\frac{1}{2}KA^2\\\rightarrow \ \frac{3U}{2}=\frac{1}{2}KA^2\\\rightarrow \ U=\frac{1}{3}KA^2\\\rightarrow \ \frac{Kx^2}{2}=\frac{1}{3}KA^2\\\\x=\sqrt{\frac{2}{3}}A\\x=0.4\ m[/tex]
What is the precision for each measurement for the online simulation. What would be the precision for force
Answer:
Unit of precision for force is the Newton.
Explanation:
It is the official unit used to describe force in science and mostly abbreviated with the symbol N.
which is not an insulator?
A wood
B plastic foam
C aluminum foil
D fiberglass
Answer:the answer is C aluminum foil
Explanation:
What are forces like in a collision?
Answer:
equal in magnitude and opposite in direction.
Explanation:
I don't have 1 I just knew -_('-')_-
A boat moves through the water of a river at 8 m/s relative to the water, regardless of the boat's direction. If the water in theriver is flowing at 1.9 m/s, how long does it take the boat to makea round trip consisting of a 260 m displacement downstream followedby a 260 m
Answer:
68.88 m/s
Explanation:
downstream speed = 8+1.9=9.9 m/s
upstream speed = 8-1.9= 6.1 m/s
Therefore, total time taken would be 260/9.9+260/6.1 = 26.26+42.62 =
68.88 m/s
Imagine you were lifting very heavy jugs to the top of a house. You can either use the stairs on the left or push them up the inclined plane on the right. Which option is easier
Answer:
Use the stairs
Explanation:
This is easier because if you go on the stairs you can rest if you get tired but if you go on the inclined plane then the weight of the jugs will make you slower than you already are and you may end up going back down instead of up where you wanna go.
If a wheel rotates 5 times in 90 seconds, what is the period and frequency
Answer:
i think it should be 18
Explanation:
11. Which element in Figure 15.17 is likely to be a the best conductor of electricity ?
Answer:
first where is figure...
silver the is best conducter of electricity.
A force can change an object's direction and cause friction
True or False
Answer:
This is very true
Explanation:
The force from impact can easily change it to expanse in a different direction.
I hope this helped you very much :)
Calculate the momentum of a Lion of mass 130-kg and moving at a speed of 22.3 m/s [W]
Answer:
289.9 kg.m/sExplanation:
The momentum of an object can be found by using the formula
momentum = mass × velocity
From the question we have
momentum = 130 × 22.3
We have the final answer as
289.9 kg.m/sHope this helps you
What is the potential energy of a 2500 g object suspended 5 m above the earth's surface?
kilograms. convert mass to kilograms to solve this problem.
Answer:
Explanation:
Potential energy, which is the energy a body assumes at a position, can be calculated using the formula:
P.E = m × g × h
Where;
m = mass (kg)
g = acceleration due to gravity (10m/s²)
h = height (m)
The intensity at a distance of 6 m from a source that is radiating equally in all directions is 6.0\times 10^{-10} W/m^2. What is the power emitted by the source
Answer:
P = 271 nW
Explanation:
If the source is radiating equally in all directions, it can be treated as a point source, so all points located at the same distance of the source, have the same intensity I, which is related to the power by the following expression:[tex]I = \frac{P}{A} =\frac{P}{4*\pi *r^{2} } (1)[/tex]
Solving for P, we get:[tex]P = I*4*\pi *r^{2} = 6.0e-10 W/m2 * 4 * \pi *(6m)^{2} =271 nW (2)[/tex]
A 1.3-kg model airplane flies in a circular path on the end of a 23-m line. The plane makes
4.3 revolutions each minute.
a. What is the period of the motion?
b. What is the speed of the plane?
c. What is the acceleration of the model plane?
d. How much force must the line exert on the plane to keep it moving in the circular
motion?
(a) The plane makes 4.3 revolutions per minute, so it makes a single revolution in
(1 min) / (4.3 rev) ≈ 0.2326 min ≈ 13.95 s ≈ 14 s
(b) The plane completes 1 revolution in about 14 s, so that in this time it travels a distance equal to the circumference of the path:
(2π (23 m)) / (14 s) ≈ 10.3568 m/s ≈ 10 m/s
(c) The plane accelerates toward the center of the path with magnitude
a = (10 m/s)² / (23 m) ≈ 4.6636 m/s² ≈ 4.7 m/s²
(d) By Newton's second law, the tension in the line is
F = (1.3 kg) (4.7 m/s²) ≈ 6.0627 N ≈ 6.1 N
A water balloon is dropped off the top of a building and bursts when it hits
the ground 6 seconds later. What is the height of the building?
Answer:
The building is 176.4 meters high.
Explanation:
We use the formula for kinematics of an accelerated object (in this case acceleration of gravity):
Distance travelled = 1/2 g t^2
Distance travelled = 1/2 9.8 (6)^2 = 176.4 meters
A construction laborer holds a 20 kg sheet of wallboard 3 m above the floor for 4 seconds. During these 4 seconds how much power was expended on the wallboard
Answer:
zero
Explanation:
no distance has moved while holding the sheet...so no distance means no workdone..no workdone means no power...
How must a tennis serve start
Answer/Explanation:
When serving the primary serve, remain behind the benchmark between the middle imprint and the correct sideline. The ball is hit corner to corner into the administration box on the opposite side of the net, on the contrary side of the middle imprint from which the worker is serving.
horizontal range = 200m, maximum height= 25m find the angle of projection.
Answer:
θ = 26.6°
Explanation:
Formula for maximum height is;
h = u²sin²θ/2g
We are told maximum height is 25 m, thus;
u²sin²θ/2g = 25 - - - - (eq 1)
Formula for horizontal range is;
R = u²sin2θ/g
In Mathematics, sin2θ = 2sinθcosθ
So; R = 2u²sinθcosθ/g
R = 2u²sinθcosθ/g
We are given Horizontal range = 200 m.
Thus;
2u²sinθcosθ/g = 200 - - - - (eq 2)
Divide eq 1 by eq 2 to get;
200/25 = 4cosθ/sinθ
8 = 4cosθ/sinθ
4/8 = sinθ/cosθ
0.5 = tan θ
θ = tan^(-1) 0.5
θ = 26.6°
A 15-kg wagon is pulled to the right across a surface by a tension
of 100 newtons at an angle of 30 degrees above the horizontal.
A frictional force of 20 newtons to the left acts simultaneously.
What is the acceleration of the wagon?
Answer:
4.44 m/s^2
Explanation:
A 15-kg wagon is pulled to the right across a surface by a tension of 100 newtons at an angle of 30 degrees above the horizontal. A frictional force of 20 newtons to the left acts simultaneously.The acceleration of the wagon 4.44 m/s².
What is acceleration?The rate at which an item changes its velocity is known as acceleration, a vector quantity. If an object's velocity is changing, it is acceleration.
Given in the question a 15 kg wagon is pulled to the right across a surface by a tension of 100 newtons at an angle of 30 degrees above the horizontal. A frictional force of 20 newtons to the left acts simultaneously, then the acceleration is 4.44 m/s².
The acceleration of the wagon 4.44 m/s².
To learn more about acceleration refer to the link:
brainly.com/question/12550364
#SPJ2
Which describes velocity?
Answer:
Velocity is the rate at which the position changes. The average velocity is the displacement or position change per time ratio.
Explanation:
Answer:
The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. Velocity is equivalent to a specification of an object's speed and direction of motion (e.g. 60 km/h to the north).
Other units: mph, ft/s
In SI base units: m/s
Explanation:
i dont know if this helps.
1 point
After being cut off, Billy accelerates at a rate of 12.3m/s2 for 455 m. As he
approaches the biker who cut him off, his velocity is a ludicrous 125 m/s.
What was his initial velocity?
33.3 m/s
66.6 m/s
99.9 m/s
122.2 m/s
Answer:
The initial velocity of Billy is 66.6 m/s.
Explanation:
Given;
acceleration of Billy, a = 12.3 m/s²
distance moved by Billy, d = 455 m
final velocity of Billy, v = 125 m/s
let the initial velocity of Billy = u
Apply the following equation of motion;
v² = u² + 2ad
125² = u² + 2(12.3 x 455)
15625 = u² + 11193
u² = 15625 - 11193
u² = 4432
u = √4432
u = 66.57 m/s
u = 66.6 m/s.
Therefore, the initial velocity of Billy is 66.6 m/s.
A sample of metal with a specific heat capacity of 0.50 kk/kg.•c Is heated to 98 degrees c and then placed in an 0.055 kg sample of water at 22 degrees C
Answer:
We must identify the heat transfers that are happening here.
One is the heat transferred from the metal as it cools (
q
1
).
The second is the heat transferred to the water as it warms (
q
2
).
Per the Law of Conservation of Energy, the sum of the two heat transfers must be zero.
Explanation:
6. A yo-yo with a mass of 0.5 kg is tied to a radius of 2 m and is spinning at 3 m/s. What
is the centripetal force acting on the yo-yo?
Given that,
Mass of yo-yo, m = 0.5 kg
Radius of the path, r = 2 m
Speed of the object, v = 3 m/s
To find,
The centripetal force acting on the yo-yo.
Solution,
The formula for the centripetal force is given as follows :
[tex]F=\dfrac{mv^2}{r}\\\\F=\dfrac{0.5\times (3)^2}{2}\\\\F=2.25\ N[/tex]
So, the magnitude of centripetal force acting on the y-yo is 2.25 N.