Which one of the following statements regarding motion is correct?

Which one of the following statements about speed and velocity is correct?

Which one of the following statements regarding simple pendulum is correct ? Simple pendulum has a time period independent of amplitude :

Which one of the following about different frictional forces is correct?

Which one of the following equations related to the motion of an object is NOT correct? (Symbols carry their usual meanings)

An electron and a proton starting from rest are accelerated through a potential difference of 1000 V. Which one of the following statements in this regard is correct?