A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction.
Force , Newton's Laws of Motion and MomentumOleepari
Force and Newton’s laws : Force and Motion, Newton’s Laws of Motion, Action and Reaction
forces, Inertia of a body, Inertia and mass, Momentum, Force and Acceleration. Elementary
idea of conservation of Momentum
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Force , Newton's Laws of Motion and MomentumOleepari
Force and Newton’s laws : Force and Motion, Newton’s Laws of Motion, Action and Reaction
forces, Inertia of a body, Inertia and mass, Momentum, Force and Acceleration. Elementary
idea of conservation of Momentum
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
2. What is a Force?
• In science, the word force has a simple and
specific meaning.
• A force is a push or a pull
• When one object pushes or pulls another
object, you say that the first object exerts a
force on the second object.
• You exert a force on a computer key when you
push it and on a chair when you pull it away
from a table.
3. • Like velocity and acceleration, a force is
described by its strength and by the direction
in which it acts.
• If you push a door, you exert a force in a
different direction than if you pull on the door.
• The strength of a force is measured in the SI
unit called the newton (N).
4. • This unit is named after the English scientist
and mathematician Sir Isaac Newton.
• You exert about one newton of force when you
lift a small lemon.
• The direction and strength of a force can be
represented by an arrow.
• The arrow points in the direction of a force.
• The length of the arrow tells you the strength
of the force – the longer the arrow, the greater
the force.
5. Combining Forces
• Often, more than a single force acts on an
object at one time.
• The combination of all forces acting on an
object is called the net force.
• The net force determines whether an object
moves and also in which direction it moves.
6. • When forces act in the same direction, the net
force can be found by adding the strengths of
the individual forces.
• In figure two, the lengths of the two arrows,
which represents two forces, are added
together to find the net force:
--------- --------- = ------------------
5N 5N 10N
7. • When forces act in opposite directions, they
also combine to produce a net force.
• However, you must pay attention to the
direction of each force.
• Adding a force acting in one direction to a
force acting in the opposite direction is the
same as adding a positive number to a negative
number.
8. • So when two forces act in opposite directions,
they combine by subtraction.
• The net force always acts in the direction of
the greater force.
----- ---------- = -----
5N 10N 5N
9. • If the opposing forces are of equal strength,
there is no net force.
• There is no change in the object’s motion.
----- ----- = 0N
5N 5N
10. Unbalanced Forces
• Whenever there is a net force acting on an
object, the forces are unbalanced.
• Unbalanced forces can cause an object to start
moving, stop moving, or change direction.
• Unbalanced forces acting on an object result in
a net force and cause a change in the object’s
motion.
11. • Figure 3 shows two people exerting forces on a
box.
• When they both push a box to the right, their
individual forces add together to produce a net
force in that direction.
• Since a net, or unbalanced, force acts on the
box, the box moves to the right.
12. • When the two people push the box in opposite
directions, the net force on the box is the
difference between their individual forces.
• Because the boy pushes with a greater force
than the girl, their forces are unbalanced and a
net force acts on the box to the right.
• As a result, the box moves to the right.
13.
14. Balanced Forces
• When forces are exerted on an object, the
object’s motion does not always change.
• In an arm wrestling contest, each person exerts
a force on the other’s arm, but the two forces
are exerted in opposite directions.
• Even though both people push hard, their arm
position may not change.
15. • Equal forces acting on one object in opposite
directions are called balanced forces.
• Each force is balanced by the other.
• Balanced forces acting on an object do not change the
object’s motion.
• When equal forces are exerted in opposite directions,
there is no net force.
• In Figure 3, when two people push on the box with
equal force in opposite directions, the forces cancel
out.
• The box does not move.