The answer would be Newton’s Second Law
Complete Question
The complete question is shown on the first and second uploaded image
Answer:
The velocity is
Explanation:
The kinetic energy of the 9 kg can be determined by these expression
Kinetic energy of 9 kg block = initial energy stored - energy lost as a result of friction
Now to obtain the initial energy stored
Let U denote the initial energy stored and

Where x is the length the spring is displaced
k is the force constant of the string


Now referring to the formula above
i.e Kinetic energy of 9 kg block = initial energy stored - energy lost as a result of friction



and we are told that coefficient of friction = 0.4 and the mass is 9 kg ,the acceleration due to gravity
this displacement length of spring = 0.6
Therefore 
Answer:
No
Explanation:
No, overload heaters do not open to break the circuit when their current limit is reached. These are safety device to prevent over heating.
Thermal overload relays in a motor are intended to protect the conductors (windings). Such safety devices are made to maintain the current flow in a circuit at a safety level so as to avoid overheating of the circuitry conductors. And the excess of current is often called as over current.
Answer:
0.833 N
Explanation:
Formula for Kinetic Energy 
Formula for Potential Energy 
First we need to find the vertical distance between the maximum-angle position and the pendulum lowest point:
Using the swinging point as the reference, the vertical distance from the maximum-angle (34 degree) position to the swinging point is:

At the lowest position, pendulum is at string length to the swinging point, which is 1.2 m. Therefore, the vertical distance between the maximum-angle position and the pendulum lowest point would be
y = 1.2 - 1 = 0.2 m.
As the pendulum is traveling from the maximum-angle position to the lowest point position, its potential energy would be converted to the kinetic energy.
By law of energy conservation:




Substitute
and y = 0.2 m:

At lowest point, pendulum would generate centripetal tension force on the string:

We can substitute mass m = 0.25, rotation radius L = 1.2 m and v = 2 m/s:

Answer:
After pulses pass through each other, each pulse continues along its original direction of travel, and their original amplitudes remain unchanged.
Explanation:
Constructive interference takes place when two pulses meet each other to create a larger pulse.