(a) 392 N/m
Hook's law states that:
(1)
where
F is the force exerted on the spring
k is the spring constant
is the stretching/compression of the spring
In this problem:
- The force exerted on the spring is equal to the weight of the block attached to the spring:

- The stretching of the spring is

Solving eq.(1) for k, we find the spring constant:

(b) 17.5 cm
If a block of m = 3.0 kg is attached to the spring, the new force applied is

And so, the stretch of the spring is

And since the initial lenght of the spring is

The final length will be

Answer:
Solid-state
Explanation:
A solid-state device can be defined as a crystalline material that is typically made up of semiconductor and as such controls the number and rate of flow of charged carriers such as holes or electrons.
Some examples of a solid-state device are light emitting diodes (LED), integrated circuit (IC), Transistors, liquid crystal display (LCD) etc.
A solid-state device such as a transistor, refers to a semiconductor component that is used to control the flow of voltage or current and as a gate (switch) for electronic signals. Thus, a transistor allows for the amplification, control and generation of electronic signals in a circuit.
Hence, solid-state devices need constant power to operate. The timing functions are initiated by the presence or absence of a separate "trigger" signal.
Basically, these solid-state devices use the optical and electrical properties of semiconductor components such as transistors, triacs, thyristors, diodes to perform its input-output switching and isolation functions.
Answer:
3A
Explanation:
Rtoal=R1+R2+R3=5+10+15=30
I=V/R 90/30
I=3
Pulling a dogs leash: inertia
1. First blank is A. Conductors
Second blank is D. Insulators
2. C. Heat