Answer:
0.4 m/s
Explanation:
Law of conservation of momentum tell us that the change in momentum of the hammer will be equal to the change in momentum of the astronaut
change in momentum of hammer = change in momentum of astronaut
2 kg (14 m/s - 0 m/s) = 70 kg * (v-0)
v = 0.4 m/s
Answer:
Explanation:
a ) The velocity will never be zero . The velocity will be minimum at the highest point of projectile, which will be equal to the horizontal component of the initial velocity.
b ) The velocity will be minimum when its kinetic energy will be minimum . Kinetic energy will be minimum when its potential energy will be maximum.
Its potential energy will be maximum at the highest point so velocity will be minimum at the highest point.
c ) Velocity will never be the same as initial velocity because constant force of gravitation is acting on the projectile all the time.
d ) At the moment when the projectile returns back and hits the ground, the speed becomes equal to the initial speed ( at t = 0 ) because its kinetic energy becomes the same as initial energy , the height becoming zero.
Answer:
Explanation:
According to newton's law of gravitation , equal force of attraction are applied on two masses m₁ and m₂ placed at distance d . This force is given by the expression
F = G m₁ m₂ / d²
If one of the masses be earth with mass M then d = radius of earth R
Force F = G Mm₁ / R²
this force is applied on both the earth and mass m₁ in equal magnitude and in opposite direction.
In the formula F is proportional to m₁
among the given objects in the question , m₁ of object varies in the following order.
skyscraper > car > human being > basket ball
So Force F on the earth by them will also vary in the same order.
Well, it's really dangerous to try and visualize physical models for things
of this size. But if you must, then it's something like this:
-- The nucleus is a tight-packed bunch of protons and neutrons, located
at the center of each atom.
-- The electrons live all around the nucleus, in a space far from it.
A description of the relative sizes that I read more than 60 years ago
and always stuck with me goes like this: The nucleus in the middle
and the electrons whizzing around it have a size-relationship that's
about the same as a bunch of grapes in the middle of the state of Texas.
This also tells us that matter is mostly empty space !
-- In Bohr's model of the atom, he described the whole thing very much
like a miniature solar system ... the electrons are tiny, solid little balls,
orbiting the nucleus like planets around the sun.
We learned later that it's impossible to talk about things like "how big is
the electron" or "where is the electron" or "how much momentum does
the electron have". The best we can do is talk about a 'cloud' around the
nucleus ... it has some mass and some negative charge, and portions
of it somehow exist at different levels of energy, and can jump to
different levels.
This is NOT because we don't have good enough technology yet to
zoom in on the electrons, and at some time in the future we'll be able
to sharply see where they are and how fast they're moving. It's because
on the scale of atomic dimensions, there is NO SUCH THING as "where
is it" or "how big is it" or "how fast is it moving". These don't exist.
"Location" is described in terms of probability, objects behave like solid
waves, and an object can have this much energy or that much energy
but NO AMOUNT OF ENERGY IN BETWEEN.
Weird ? Hard to understand ? You said it !
BTW ... the answer to the question is ' A ' .
Answer:
: the minimum frequency of radiation that will produce a photoelectric effect
:DD
Mark me as brainliest
If u find helpful
