I know you are Indian by your question, HC Verma class 9 or 11 !!
if you got any problem, comment !!
Answer:
Explanation:
We define the linear density of charge as:

Where L is the rod's length, in this case the semicircle's length L = πr
The potential created at the center by an differential element of charge is:

where k is the coulomb's constant
r is the distance from dq to center of the circle
Thus.

Potential at the center of the semicircle
Answer:
Length of the stake will be 0.3623 m
Explanation:
We have given energy required to fully drive a stake into ground = 0.30 KJ = 300 J
Average resistive force acting on the floor is equal to F = 828 N
We have to find the length of the stake
We know that work done is given by
W = Fd, here W is work done , F is average force and d is the length of the stake
So 300 = 828×d
d = 0.3623 m
So length of the stake will be 0.3623 m
Explanation:
3
i believe that they are all going at 3.2 meters each, I did 4 times 0.8
Answer:

Explanation:
<u>Second Newton's Law</u>
It allows to compute the acceleration of an object of mass m subject to a net force Fn. The relation is given by

The net force is the sum of all vector forces applied to the object. The block has two horizontal forces applied (in absence of friction): The 30 N force acting to the right and the 60 N force to the left. The positive horizontal direction is assumed to the right, so the net force is

Thus, the acceleration can be computed by


The negative sign indicates the block is accelerated to the left