Answer:
Explanation:
The sandpaper block did not move because the forces of friction and gravity were balanced.
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.
The resistance expected of the heater is 50.1 ohms.
<h3>What is resistance?</h3>
Resistance can be defined as the opposition to the flow of electric current in an electric circuit. The S.I unit of resistance is Ohms (Ω).
To calculate the resistance of the heater, we use the formula below.
<h3>Formula:</h3>
- R = V²/P............. Equation 1
Where:
- R = Resistance of the heater
- P = Power of the heater
- V = Voltage supplied to the heater
From the question,
Given:
- V = 480 V
- P = 4.6 kW = 4600 W
Substitute these values into equation 1
- R = (480²)/4600
- R = 50.1 ohms.
Hence, the resistance expected of the heater is 50.1 ohms.
Learn more about resistance here: brainly.com/question/17563681
