An object moves with constant acceleration 4.20 m/s2 and over a time interval reaches a final velocity of 10.4 m/s.

(a) If its original velocity is 5.20 m/s, what is its displacement during the time interval?

V^2 = Vo^2 + 2a*d.

V = 10.4 m/s, Vo = 5.20 m/s, a = 4.20 m/s, d = ?.

To find the displacement of the object during the time interval, we need to use the equations of motion.

First, let's list down the given values:
Initial velocity (u) = 5.2 m/s
Acceleration (a) = 4.2 m/s^2
Final velocity (v) = 10.4 m/s

We can use the equation of motion to relate displacement, initial velocity, final velocity, and acceleration:

v^2 = u^2 + 2aS

where v is the final velocity, u is the initial velocity, a is the acceleration, and S is the displacement.

Rearrange the equation to solve for S:

S = (v^2 - u^2) / (2a)

Now, substitute the given values into the equation:

S = (10.4^2 - 5.2^2) / (2 * 4.2)

Calculate the expression:

S = (108.16 - 27.04) / 8.4

S = 81.12 / 8.4

S = 9.64 meters

Therefore, the object's displacement during the time interval is 9.64 meters.