Answer:
The system's potential energy is -147 J.
Explanation:
Given that,
Energy = 147 J
We know that,
System is isolated and it is free from external forces.
So, the work done by the external forces on the system should be equal to zero.

We need to calculate the system's potential energy
Using thermodynamics first equation

Put the value into the formula


Hence, The system's potential energy is -147 J.
yah set up an experiment do u have the rocks with u?
A 500 g ball swings in a vertical circle at the end of a 1.4-m-long string. when the ball is at the bottom of the circle, the tension in the string is 18 n.
Answer:
Option d is correct.
Explanation:
We know , resistance of a body is directly proportional to its length and inversely proportional to its area.
( Here,
is constant dependent on object material )
Writing
also :
( since they are of same material therefore,
is same.)
Now , if
.
Then 
Therefore, option d. is correct.
Hence, this is the required solution.
Answer:
The relative density of the second liquid is 7.
Explanation:
From archimede's principle we know that the force that a liquid exerts on a object equals to the weight of the liquid that the object displaces.
Let us assume that the volume of the object is 'V'
Thus for the liquid in which the block is completely submerged
The buoyant force should be equal to weight of liquid
Mathematically

Thus for the liquid in which the block is 1/7 submerged
The buoyant force should be equal to weight of liquid
Mathematically

Comparing equation 'i' and 'ii' we see that

Since the first liquid is water thus 
Thus the relative density of the second liquid is 7.