00:01
Hello students, in this question a block of mass m is attached to the wall by a spring.
00:10
So, in this manner and initially it is neither compressed or nor stretched and there is no friction between the block and the spring.
00:24
So, for this for the first question we have to consider the system sb, system sb that is the both the spring and the block.
00:37
In this for the first question we have to state the whether the forces acting on the system sb is positive, negative or zero.
00:49
So, in this case two horizontal forces will be there.
00:56
So, two horizontal forces will be there.
01:03
The one is the force due to spring and another one is the force due to the string, force due to string which is used to pull the block towards the right side.
01:28
So, in this case the force due to the string is positive since the force is in same direction, same direction as the displacement of the block, displacement of the block.
01:56
That is in this case the block is pulled towards the right side and this force due to string will be acting in the same direction.
02:06
So, this force is positive.
02:08
And another case the work done by the spring force that is negative because here the force acts in opposite direction to the displacement of the block.
02:24
So, opposite direction.
02:31
So, for the first question the force due to spring is negative and the force due to the string is positive.
02:41
This is for first part of the question.
02:45
Next we have to complete the energy bar diagram for the s -b system.
02:50
So, here first delta u is the potential energy, delta k is the kinetic energy and w is the total energy or this is the total work done.
03:03
First we will calculate the energy for the spring...