Answer:
it gravitional pull on earth will increased becauste it is compress to a form of moon which is comperatively smaller so the gravitonal pull on per cm of earth will incrased so we can say that there will be change in acceleration due to gravity
Answer:
7 s
Explanation:
u = Initial velocity of rock = 12.2 m/s
= Angle of throw = 
x = Displacement in x direction = 25 m
Displacement in x direction is given by

Time taken to reach the ground is 7 s.
Answer:
The electric force between them if the pieces of grain are 2 cm apart is
.
Explanation:
Given:
Charge on one grain, 
Charge on another grain, 
Separation between them, 
Electric force acting between two charges
separated by a distance
is given as:

Where,
is Coulomb's constant equal to
.
Now, plug in all the values and solve for
.

Therefore, the electric force between them if the pieces of grain are 2 cm apart is
.
Answer:
The solid sphere will reach the bottom first.
Explanation:
In order to develop this problem and give it a correct solution, it is necessary to collect the concepts related to energy conservation. To apply this concept, we first highlight the importance of conserving energy so we will match the final and initial energies. Once this value has been obtained, we will concentrate on finding the speed, and solving what is related to the Inertia.
In this way we know that,


We know as well that the lineal and angular energy are given by,

And the tangential kinetic energy as

Where
Replacing

Re-arrange for v,

We have here three different objects: solid cylinder, hollow pipe and solid sphere. We need the moment inertia of this objects and replace in the previous equation found, then,
For hollow pipe:




For solid cylinder:




For solid sphere,




Then comparing the speed of the three objects we have:

