The person is walking 3.5 miles an hour
Fundamental quantity : quantities which are independent on other physical quantity .
ex: length,mass,time, current, amount of substance, luminous intensity, thermodynamic temperature,
Derived quantity : quantities which are depend on fundamental quantities.
ex: Area, volume, density, speed, acceleration, force, velocity etc.
Normally, when something gets colder, its electrical resistance gets smaller. This is true of component-A in the drawing ... a simple resistor.
The component labeled 'B' has a strange and unusual symbol, and it's not a simple resistor. It's a "thermistor". The word "thermal" always has something to do with heat, and "thermistor" comes from "thermal resistor. These things can be manufactured either way ... using different materials, a thermistor can be manufactured so that its resistance goes UP, or goes DOWN, or doesn'tchange when it gets colder. I'm pretty sure that's what's going on here.
When this circuit gets colder, resistance-A gets smaller, but resistance-B either gets bigger OR doesn't change. Either way, the voltage across B increases. Since the LED is connected directly across B, the current through it depends on that voltage, so the LED gets more current, and becomes brighter, when A and B both get colder.
This circuit could actually be a very useful device. If you took out the LED and put a voltmeter in its place, then the reading on the voltmeter would tell you the temperature of wherever you put the two components A and B.
Answer: 25 Ohms
Explanation:
From this question, the following parameters are given:
Voltage V = 1.5 v
Current I = 0.03A
From Ohm's law;
V = IR
Where R = resultant resistance of the two resistors.
Substitute V and I into the formula and make resultant R the subject of formula.
1.5 = 0.03 × R
R = 1.5/0.03
R = 50 Ohms
From the question, it is given that Thr two equal resistors are connected in series.
R = R1 + R2
But R1 = R2
50 = 2R1
R1 = 50/2
R1 = 25
R1 = R2 = 25 Ohms
Therefore, the resistors must each have a value of 25 Ohms
Velocity = displacement (distance)/time
v=80m/4s
v=20m/s
velocity = 20 meters per second
