T = 4.25 ms = 4 x 10⁻³ s, the time for rebound
v₁ = 25.5 m/s, the impacting velocty
v₂ = -19.5 m/s, the rebounding velocity (n the opposite directon)
The change in velocity is
v₂ - v₁ = - (25.5+19.5) = -45 m/s
The acceleration is
a = (-45 m/s)/(4 s) = -11.25 m/s²
The negative sign indicates that the final velocity is opposiye to the impact velocty.
Answer: The magnitude of the acceleration is 11.25 m/s²
I really don’t know but I think it’s D
Earth's magnetic field is the force acting on the compass needle to cause it to point northeast.
To develop this problem it is necessary to apply the optical concepts related to the phase difference between two or more materials.
By definition we know that the phase between two light waves that are traveling on different materials (in this case also two) is given by the equation

Where
L = Thickness
n = Index of refraction of each material
Wavelength
Our values are given as





Replacing our values at the previous equation we have




Therefore the thickness of the mica is 6.64μm