Answer:
(a) W=1.20×10⁴J
(b) U= -5.46×10⁴J
(c) Q= -4.26×10⁴J
Explanation:
Given that student does 1.20×10⁴J work
(a) W=1.20×10⁴J
Work done by student,so positive sign
During the process, his internal energy decreases by 5.46×10⁴J.
(b) U= -5.46×10⁴J.
As the Energy decreases therefore negative sign
For (c) Q
We know the formula
Answer: 2.13 × 10⁻⁷ N
Explanation:
Gravitational force exists between any two bodies having mass.
Force of gravity is given by:
It is given that, mass of newborn baby is M = 2.50 kg
Mass of the doctor, m = 80.0 kg
Distance between the two, r = 0.250 m
Gravitational constant, G = 6.67 × 10⁻¹¹ N m²/kg²
⇒F = (6.67 × 10⁻¹¹ N m²/kg² × 2.50 kg × 80.0 kg )÷ (0.250 m)² = 2.13 × 10⁻⁷ N
Thus, the force of gravity between new born baby and doctor is 2.13 × 10⁻⁷ N.
Answer:
Explanation:
Motor rating is given in horsepower (hp), it will be converted in watt (W).
Standard to install circuit breaker for an electric circuit is usually 20% ~ 25% more than the Rated Current of the circuit
while
Standard to install overload relay for an electric circuit is usually 20% ~ 25% more than the Running Current of the circuit.
So, to find the maximum capacity of the circuit breaker, rated current of the motor will be multiplied by 1.2 ~ 1.25
Step by Step Explanation:
30hp = 22371W (as 1hp = 745.7)
Assuming unity power factor (cosФ=1) and 208V phase to phase voltage:
Rated Power (watt) = √3 . V.I. cosФ
<em>{if 208V is phase to neutral voltage, then use following formula:</em>
<em> Rated Power (watt) = 3 . V.I. cosФ}</em>
Rated Current = <u>62.169A</u>
So, required maximum rating for circuit breaker is:
20% to 25% of the rated current = 62.17*1.2 ~ 62.17*1.25
=74.6A ~ 77.7A
Hence, any breaker between the above mentioned rating will be appropriate.