Kelly is pulling on the rock and the earth, but the rock's mass and the earth's mass overpowers her mass, so she is pushed up by the rock and earth.
Answer:
1.) 10.61 A
2.) 0.27 A
Explanation:
Given that a sinusoidal A.C has a maximum value of 15A.
1) What are its r.m.s values?
ii) If the time is recorded from the instant the current is zero and is becoming
positive, what is the instantaneous value of the current after 1/300s, given the
frequency is 50 Hz.
Solution.
1.)
The r.m.s current = peak current/root 2
The r.m.s current = 0.7071 × 15
The r.m.s current = 10.61 A
2.)
Given that
Time = 1/300 s
Frequency = 50 Hz
Instantaneous current can be calculated by using the formula
I = I sin wt
Where w = 2πf
Instantaneous current = 15( sin 2πft)
I = 15 × sin ( 2 × 3.143 × 50 × 1/300 )
I = 15 × sin ( 1.047 )
I = 15 × 0.01827
I = 0.27 A
Therefore, the instantaneous current is 0.27A
Answer:
The frequency the listener hears is 911.765 Hz.
Explanation:
The speed of a sound is 340 m/s
The speed of listener is 30 m/s in a direction away from the whistle.
The speed of the listener with respect to the sound waves from the whistle
= ( 340 - 30) m/s
= 310 m/s
This because the direction of the sound waves from the whistle and the direction of travel of the listener are the same, that is, both are traveling away from the whistle.
Therefore from the formula we get
⇒ 
⇒ 
= 
The frequency the listener hears is 911.765 Hz.
The law you need is :
lets call the constant c = 4pi*epsilon naught*r2.
where r is radius ( or seperation of the charges). epsilon naught is a constant of about 8.85*10^-12 or something like that. and 4 pi is just 4 times pi.
the actual equation is
FORCE= (q1*q2)/c
