Answer:
Explanation:
Resistivity is given by 
where A is cross-sectional area, R is resistance, L is the length and 
is the reistivity. Substituting 0.0625 for R, 3.14 × 10-6 for A and 3.5 m for L then the resistivity is equivalent to
Answer:
D
Explanation:
a neutron does not have a positive nor negative charge it remains neutral
1. a. longitudinal waves.
There are two types of waves:
- Transverse waves: in transverse waves, the oscillations of the wave occur in a direction perpendicular to the direction of propagation of the wave
- Longitudinal waves: in longitudinal waves, the oscillations of the waves occur parallel to the direction in which the waves are travelling.
So, these types of waves are called longitudinal waves.
2. d. a medium
There are two types of waves:
- Electromagnetic waves: these waves are produced by the oscillations of electric and magnetic field, and they can travel both in a medium and also in a vacuum (they do not need a medium to propagate)
- Mechanical waves: these waves are produced by the oscillations of the particles in a medium, so they need a medium to propagate - therefore, the correct choice is d. a medium
3. a. AM/FM radio
Analogue signals consist of continuous signals, which vary in a continuous range of values. On the contrary, digital signals consist of discrete signals, which can assume only some discrete values. For AM and FM radios, signals are transmitted by using analogue signals.
Answer:
Friction can be minimized by using lubricants like oil and grease and by using ball bearing between machine parts. A substance that is introduced between two surfaces in contact, to reduce friction, is called a lubricant. Fluid friction can be minimized by giving suitable shapes to the objects moving in the fluids.
Explanation:
hope it helps
Answer:
The spring force constant is 
.
Explanation:
We are told the mass of the ball is 
, the height above the spring where the ball is dropped is 
, the length the ball compresses the spring is 
and the acceleration of gravity is 
.
We will consider the initial moment to be when the ball is dropped and the final moment to be when the ball stops, compressing the spring. We supose that there is no friction so the initial mechanical energy 
is equal to the final mechanical energy 
:
Initially there is only gravitational potential energy because the force of the spring isn't present and the speed is zero. In the final moment there is only elastic potential energy because the height is zero and the ball has stopped. So we have that:
If we manipulate the equation we have that:
