Answer:
a)-2m/s^2
b)27.2m/s
Explanation:
Hello! The first step to solve this problem is to find the mass of the block remembering that the definition of weight force is mass by gravity (g=9.8m / s ^ 2)
W=455N=weight
W=mg
W=455N=weight

The second step is to draw the free body diagram of the body (see attached image) and use Newton's second law that states that the sum of the forces is equal to mass by acceleration

for point b we use the equations of motion with constant acceleration to find the velocity

Where
Vf = final speed
Vo = Initial speed
=0
A = acceleration
=2m/s
X = displacement
=6.8m
Solving

Answer: The copper wiring most likely caused the mini-refrigerator fire.
Explanation: A mini-refrigerator may have one or more evaporator fan motors. These motors have copper wiring. In some situation these copper wires gets overheated. It may result to the firing of the mini-refrigerator.
Therefore, the mini-refrigerator fire was most likely caused by copper wiring.
In a series circuit the total current is the same throughout resistors and so:

The voltage is distributed throughout the resistors and so:

and the total resistance can be calculated by adding up the resistors resistance:

First thing is to calculate the total resistance and so:

And by Omh's law V=IR we have:

And so the total current of the circuit is 1.2 amps i.e. 1.2 A.
Answer: Real image
Explanation:
converging lens will only produce a real image if the object is located beyond the focal point (i.e., more than one focal length away).