Answer: Rock require larger drag force and to achieve it rock need to move at a very high terminal velocity.
Explanation: Terminal velocity is defined as the final velocity attained by an object falling under the gravity. At this moment weight is balanced by the air resistance or drag force and body falls with zero acceleration i.e. with a constant velocity.
Case 1: Terminal velocity of a piece of tissue paper.
The weight of tissue paper is very less and it experiences an air resistance while falling downward under the effect of gravity.
Downward gravitational force, F = mg
Upward air resistance or friction or drag force will be 
So, paper will attain terminal velocity when mg =
Case 2: Rock is very heavy and require larger air resistance to balance the weight of rock relative to the tissue paper case.
Downward force on rock, F = Mg
Drag force = 
Rock will attain terminal velocity when Mg =
Mg > mg
so, >
And rock require larger drag force and to achieve it rock need to move at a very high terminal velocity.
B. They are rearranged.
The First Law of Thermodynamics states that matter and energy can not be created or destroyed.
Answer:
The kinetic energy of the particle will be 12U₀
Explanation:
Given that,
A particle is launched from point B with an initial velocity and reaches point A having gained U₀ joules of kinetic energy.
Constant force = 12F
According to question,
The kinetic energy is
....(I)
Constant force = 12F
A resistive force field is now set up ,
Resistive force is given by,
When the particle moves from point B to point A then,
We need to calculate the kinetic energy
Using formula for kinetic energy
Put the value of 
Now, from equation (I)
Hence, The kinetic energy of the particle will be 12U₀.
Answer:
0.625 c
Explanation:
Relative speed of a body may be defined as the speed of one body with respect to some other or the speed of one body in comparison to the speed of second body.
In the context,
The relative speed of body 2 with respect to body 1 can be expressed as :
Speed of rocket 1 with respect to rocket 2 :
Therefore, the speed of rocket 1 according to an observer on rocket 2 is 0.625 c
