To solve this problem we will apply the concepts related to gravity according to the Newtonian definitions. From finding this value we will use the linear motion kinematic equations to find the time. Our values are
Comet mass 
Radius 
Rock was dropped from a height 'h' from surface = 1m
The relation for acceleration due to gravity of a body of mass 'm' with radius 'r' is

Where G means gravitational universal constant and M the mass of the planet


Now calculate the value of the time




The time taken for the rock to reach the surface is t = 87.58s
Answer:

Explanation:
An object is at rest along a slope if the net force acting on it is zero. The equation of the forces along the direction parallel to the slope is:
(1)
where
is the component of the weight parallel to the slope, with m being the mass of the object, g the acceleration of gravity,
the angle of the slope
is the frictional force, with
being the coefficient of friction and R the normal reaction of the incline
The equation of the forces along the direction perpendicular to the slope is

where
R is the normal reaction
is the component of the weight perpendicular to the slope
Solving for R,

And substituting into (1)

Re-arranging the equation,

This the condition at which the equilibrium holds: when the tangent of the angle becomes larger than the value of
, the force of friction is no longer able to balance the component of the weight parallel to the slope, and so the object starts sliding down.
Answer:
Reproducibility of research
Explanation:
The principle of science that explains why similar experimental investigations conducted in different parts of the world could result in the same outcome is referred to as reproducibility.
<em>A good research or experiment in science must be reproducible, otherwise, the outcome of such an experiment might become inadmissible within the scientific community. It is a core principle of the scientific method that similar results should be obtained when an experiment or observational study conducted in one place is repeated in another place with the same procedure. Hence, an experiment must be reproducible in science in order for the outcome of such an experiment to be part of the general scientific knowledge. </em>
Answer:
The graphs are attached
Explanation:
We are told that he starts with a constant speed of 25 m/s for a distance of 100 m.
At constant velocity, v = distance/time
time(t) = distance(d)/velocity(v)
t1 = 100/25
t1 = 4 s
Now, we are told that he applies his brakes and accelerates uniformly to a stop just as he reaches a wall 50m away.
It means, he decelerate and final velocity is zero.
Thus;
v² = u² + 2as
0² = 25² + 2a(50)
25² = - 100a
625 = - 100a
a = - 625/100
a = - 6.25 m/s²
v = u + at
0 = 25 + (-6.25t)
25 = 6.25t
t = 25/6.25
t = 4 s
With the values gotten, kindly find attached the distance-time and velocity-time graphs.
The kinetic energy of a moving object is given by

where m is the object's mass and v its velocity.
In our problem, the initial kinetic energy is:

while the final kinetic energy is:

So, the kinetic energy lost by Lucy and her bike is