ASTRO 7N EXAM 1 QUESTIONS AND
ANSWERS GRADED A+ LATEST UPDATE.
The force of gravity by the Sun keeps the planet in orbit around
it, but how do the planets affect the sun? ANS >>> They exert an
equally strong pull on the sun, causing it moves slightly
Newton's First Law ANS >>> An object at rest stays at rest and an
object in motion stays in motion with the same speed and in
the same direction unless acted upon by an unbalanced force.
ex: if the sun suddenly disappeared, the Earth would continue
in the direction that it was traveling in its orbit at that time
Newton's Second Law ANS >>> The acceleration of a body due to a
force will be in the same direction as the force, with magnitude
directly proportional to its mass
,Force = mass x acceleration
A smaller mas will move faster, if the same force is applied to it
Newton's Third Law ANS >>> For every action there is an equal and
opposite reaction
The Sun exerts force on planets, and they orbit it - the planets
exert equal force on Sun, but it only moves slightly because of
its very large mass relative to the planets
Surface Gravity on a Planet ANS >>> the strength of gravity: g =
m/r^2
where M is the mass of the planet and R is its radius. Note the
radius is squared but the mass is not.
More mass = more gravity.
- If the mass of a planet were twice that of another, but they
had the same radius, the gravity felt on the surface of the more-
massive one would be twice as strong.
,Larger separation = less gravity.
- If the radius of a planet were twice that of another, the gravity
is 1 / (2) 2 = 1/4 as strong.
Putting the effects of mass and radius together, you should be
able to figure out the surface gravity of Mars, relative to the
Earth.
- Mars has 1/10 the mass of the Earth and 1/2 the radius of
Earth. So, for Mars,
g = (1/10) / (1/2) 2 = (1/10) / (1/4) = 4/10
Mars has a surface gravity 4/10 that of Earth. You will need to
be able to do this type of estimate for the test, given the
numbers for mass and radius.
If I apply exactly the same amount of force to a pebble and a
boulder, what will happen ANS >>> the pebble will move faster
If the Earth were moved to half its current distance from the
sun, how would the force of gravity by the sun on the earth
change? ANS >>> it would become 4 times weaker
, Mass ANS >>> As the mass of the planet increases, the jump
height does decreases by the same factor
As the mass of the planet decreases, the jump height does
increases by the same factor
According to Newton's Second law of motion, if the net force
acting on the object increases while the mass of the object
remains constant, what happens to acceleration ANS >>>
acceleration increases
If the earth were moves to half its current distance from the
Sun, how would the force of gravity by the Sun on the Earth
change ANS >>> it would become four times weaker
What did newton's law of universal gravitation tell us about
how gravity works ANS >>> the force of gravity from the sun will
be stronger on object with more mass
If you were to sit on the ground, there would be a force due to
gravity pulling you toward the earth. which of the following is
true according to newton's third law ANS >>> you are pushing the
earth away from yourself with the same force
ANSWERS GRADED A+ LATEST UPDATE.
The force of gravity by the Sun keeps the planet in orbit around
it, but how do the planets affect the sun? ANS >>> They exert an
equally strong pull on the sun, causing it moves slightly
Newton's First Law ANS >>> An object at rest stays at rest and an
object in motion stays in motion with the same speed and in
the same direction unless acted upon by an unbalanced force.
ex: if the sun suddenly disappeared, the Earth would continue
in the direction that it was traveling in its orbit at that time
Newton's Second Law ANS >>> The acceleration of a body due to a
force will be in the same direction as the force, with magnitude
directly proportional to its mass
,Force = mass x acceleration
A smaller mas will move faster, if the same force is applied to it
Newton's Third Law ANS >>> For every action there is an equal and
opposite reaction
The Sun exerts force on planets, and they orbit it - the planets
exert equal force on Sun, but it only moves slightly because of
its very large mass relative to the planets
Surface Gravity on a Planet ANS >>> the strength of gravity: g =
m/r^2
where M is the mass of the planet and R is its radius. Note the
radius is squared but the mass is not.
More mass = more gravity.
- If the mass of a planet were twice that of another, but they
had the same radius, the gravity felt on the surface of the more-
massive one would be twice as strong.
,Larger separation = less gravity.
- If the radius of a planet were twice that of another, the gravity
is 1 / (2) 2 = 1/4 as strong.
Putting the effects of mass and radius together, you should be
able to figure out the surface gravity of Mars, relative to the
Earth.
- Mars has 1/10 the mass of the Earth and 1/2 the radius of
Earth. So, for Mars,
g = (1/10) / (1/2) 2 = (1/10) / (1/4) = 4/10
Mars has a surface gravity 4/10 that of Earth. You will need to
be able to do this type of estimate for the test, given the
numbers for mass and radius.
If I apply exactly the same amount of force to a pebble and a
boulder, what will happen ANS >>> the pebble will move faster
If the Earth were moved to half its current distance from the
sun, how would the force of gravity by the sun on the earth
change? ANS >>> it would become 4 times weaker
, Mass ANS >>> As the mass of the planet increases, the jump
height does decreases by the same factor
As the mass of the planet decreases, the jump height does
increases by the same factor
According to Newton's Second law of motion, if the net force
acting on the object increases while the mass of the object
remains constant, what happens to acceleration ANS >>>
acceleration increases
If the earth were moves to half its current distance from the
Sun, how would the force of gravity by the Sun on the Earth
change ANS >>> it would become four times weaker
What did newton's law of universal gravitation tell us about
how gravity works ANS >>> the force of gravity from the sun will
be stronger on object with more mass
If you were to sit on the ground, there would be a force due to
gravity pulling you toward the earth. which of the following is
true according to newton's third law ANS >>> you are pushing the
earth away from yourself with the same force
