Answer:
Power required, P = 175 watts
Explanation:
It is given that,
Weight of a student, F = mg = 200 N
The student climbs a flight of stairs of height, h = 7 m
Time taken, t = 8 s
We have to find the power required to perform this task. Work done per unit time is called the power required. Mathematically, it is given by :
W = work done
t = time taken
P = 175 watts
Hence, the power required to complete this task is 175 watts.
Resistance of the bulb is 7.5 ohms
Explanation:
- In a circuit, according to Ohm's Law, the potential difference (voltage) across an element is directly proportional to the current flowing through it.
That is, V ∝ I
⇒ V = IR, where R is the constant of proportionality called the resistance.
- Here, current, I = 0.4 A and potential difference, V = 3 V
Resistance, R = V/I = 3/0.4 = 7.5 ohms
Answer:
Since it us the resistance that causes the power output, it might be intuitive to think that more resistance produces more power but as P=I^2 * R one actually needs high current and low resistqnce. That means 75 W has lower resistance and higher current.
Now you may think that making the resistance very low, one gets the most power. Not so, as the circuit has wires, power source etc. All the have their resistance. In theory one gets the maximum power over a resistor when the resistor is half of the total resistance of the circuit. This in practice would be inefficient as one would lose half of the total power elsewhere. In practice circuits have fuses that limit the current and one gets the maximum power at the current the fuse is rated to. So if there is 20 A fuse, the maximum power is 2400 W and the corresponding resistance 6 ohm.
Answer:
Incomplete question
Complete question:
a constant force acts upon an object, the acceleration of the object varies inversely with its mass. When a certain constant force acts upon an object with mass 44kg , the acceleration of the object is 4m/s². If the same force acts upon another object whose mass is 11kg what is this object's acceleration?
Answer: 8m/s²
Explanation:
From the statement we deduced that acceleration varies inversely with mass where force was kept constant.
Therefore,
F/m = a or F = ma
For the first statement, substituting the mass and acceleration gives:
F = 44 x 4 = 88N
Applying the force above to the second mass gives us:
a = 88/11 = 8m/s²
Answer:
1. high frequency and high energy.
2. short wavelengths and high frequencies.
3. less energy and long wavelengths.
4. high frequencies and high energy
5. X-rays
6. infrared waves
7. radio waves.
8. Gamma Rays
9. Microwaves
10. infrared waves
