Your not really supposed to date your relative
Answer:
T = 2.4 + 2.4 = 4.8 [s]
Explanation:
In order to solve this problem, we must use the following kinematics equation and calculate the acceleration value.

Vo = inital velocity = 0
x - xo = 15 [m]
t = time = 2.4 [s]
15 = 0.5*a*(2.4)^2
a = 5.208 [m/s^2]
We can use the same equation to find the time.
30 = 15 + 0.5*(5.208)*t^2
t = 2.4 [s]
T = 2.4 + 2.4 = 4.8 [s]
The speed change : Δv = 0.41 m/s
<h3>Further explanation</h3>
Given
mass = 5.5 kg
Force = 15 N
time = 0.15 s
Required
the speed change
Solution
Newton 2nd's law
Impulse and momentum
F = m.a
F = m . Δv/t
F.t = m.Δv
Input the value :
15 N x 0.15 s = 5.5 kg x Δv
Δv = 0.41 m/s
Energy from the gravitational potential store in converted to kinetic energy. Air friction acts against the object, dissipating some energy as heat or sound. The object will continuously accelerate until the acceleration is equal to the air friction acting against it. This is when it reaches terminal velocity
Atomic number is equal to the number of protons and electrons
Atomic mass - protons = neutrons
protons + neutrons = atomic mass
I hope this helps