Excuse me, handsome guys and beautiful women, who knows the die-cutting factory in Shunde, Foshan?

It seems that (displacement) in C and D options should be changed to (time) to be reasonable.

I guess you have the wrong number.

If so, there are the following solutions.

Solution:

Let the acceleration of the object motion be a.

There are:

V=aT,VV=2as,V=(2as)^( 1/2)，

S=aTT/2,T=(2S/a)^( 1/2)

So:

① After t/2,

The speed is V-aT/2=aT/2=V/2.

The displacement is vt/2-a (t/2) (t/2)/2 = att/2-att/8 = (3/4) (att/2) = (3/4) s.

B correct

(2) After S/2,

The speed is (2as/2) (1/2) = [(2as) (1/2)]/[2 (1/2)] = v/[2 (1/2)].

The time is t-[2 (s/2)/a] (1/2) .................................................. (total time minus the time spent in the second half).

=t-[(2s/a)^( 1/2)]/[2^( 1/2)]

=T-T/[2^( 1/2)]

={ 1-[2^( 1/2)]/2}T

=( 1/2)[2-2^( 1/2)]T

correct

*****

As long as the meaning of the problem is correctly analyzed, then the appropriate formula is used.

You can make the right result.

*****