Let us examine the given situations one at a time.
Case a. A 200-pound barbell is held over your head.
The barbell is in static equilibrium because it is not moving.
Answer: STATIC EQUILIBRIUM
Case b. A girder is being lifted at a constant speed by a crane.
The girder is moving, but not accelerating. It is in dynamic equilibrium.
Answer: DYNAMIC EQUILIBRIUM
Case c: A jet plane has reached its cruising speed at an altitude.
The plane is moving at cruising speed, but not accelerating. It is in dynamic equilibrium.
Answer: DYNAMIC EQUILIBRIUM
Case d: A box in the back of a truck doesn't slide as the truck stops.
The box does not slide because the frictional force between the box and the floor of the truck balances out the inertial force. The box is in static equilibrium.
Answer: STATIC EQUILIBRIUM
Answer:
F=ma is the relationship where, F is force, m is mass and a is acceleration.
Newton's second law states that the unbalanced force applied to the object accelerates the object which is directly proportional to the force and inversely to the mass.
If we apply force to a toy car then It will accelerate.
This is how Newton's second law of motion is verified.
Answer:
(a) 
(b) 
Explanation:
Parameter given:
Electric field, E = 
(a) Electric force is given (in terms of electric field) as a product of electric charge and electric field.
Mathematically:
Electric charge, q, of an electron = 
(b) This electrostatic force causes the electron to accelerate with an equivalent force:
F = -ma
where m = mass of an electron
a = acceleration of electron
(Note: the force is negative cos the direction of the force is opposite the direction of the electron)
Therefore:
Mass, m, of an electron = 
=> 
The acceleration of the electron is 
