Explanation:
It is given that,
Angular frequency, 
Maximum displacement, A = 0.5 m at t = 0 s
We need to find the time at which it reaches its maximum speed. Firstly, we will find the maximum velocity of the object that is exhibiting SHM.


............(1)
Acceleration of the object, 

...............(2)
Using first equation of motion we can calculate the time taken to reach maximum speed.



t = 0.25 s
So, the object will take 0.25 seconds to reach its maximum speed. Hence, this is the required solution.
The lower the value of the coefficient of friction, the lower the resistance to sliding.
<u>Explanation:</u>
The coefficient of friction defines as directly proportionate with the resisting force, which is the frictional force. Hence, if there seems a decrease at coefficient of friction, then it is sure that the frictional force decreases.
We know that the frictional force on a body, is the product of coefficient of frictions and the normal forces acting on the body. Note that friction acts only, if a body is in contact, and it is of three types, static, kinetic and rolling.
The conclusion that is best supported by the data is;
D) A1 and B1 are like poles, but there is not enough information to tell whether they are north poles or south poles.