Hi :) I don’t really understand why it’s A

A

Explanation:

1. When the block moves across a table top, F(pulling) = - F(frictional).

Sum of this forces = 0, so the block moves with uniform speed.

2. When the block is pulled on top of the table covered with beads

F(pulling) > - F(frictional).

So, the sum of forces (∑F) is a number that is more than 0 and directed to the direction of movement.

So,  a = ∑F / m is positive and constant. Speed is increasing because

v(t) = v(0)+at

a is constant and  directed forward.

That means a is acceleration, and constant.

this is an example of "committed" time.

committed time, as contracted time, takes need over essential and available time since it is seen as profitable work. it alludes to the time allotted to keep up a home and family. at the point when a man is commuting using committed time this individual may feel that the drive is an obligation to family, for example, strolling youngsters to class or driving a mate to work. contracted and committed time clients may feel that their commute could really compare to the commute of important or leisure time clients on the grounds that their commute is profitable work. in this manner, they might be more disposed to pick a mechanized method of movement.