D is the correct answer, assuming that this is the special case of classical kinematics at constant acceleration. You can use the equation V = Vo + at, where Vo is the initial velocity, V is the final velocity, and t is the time elapsed. In D, all three of these values are given, so you simply solve for a, the acceleration.
A and C are clearly incorrect, as mass and force (in terms of projectile motion) have no effect on an object's motion. B is incorrect because it is not useful to know the position or distance traveled, unless it will help you find displacement. Even then, you would not have enough information to use a kinematics equation to find a.
Since in an electromagnetic wave the electric and magnetic fields are perpendicular to each other and perpendicular to the direction of motion, the electric field has to point in the z direction.
The measurement of sound is in decibels.
The answer is C as there is more force on the left side ( excess of 5 N) which therefore pushed it to the right with a force of 5 N!
According to Hooke's law, Force = spring constant x displacement of the spring. Spring constant = Force/displacement in spring = 45/0.14 = 321.42 N/m. Hope this helps!
