E = mc^2
m = e/c^2
m = 2.7*10^16/(300000^2)
m = 300000
Answer:
1.045 m from 120 kg
Explanation:
m1 = 120 kg
m2 = 420 kg
m = 51 kg
d = 3 m
Let m is placed at a distance y from 120 kg so that the net force on 51 kg is zero.
By use of the gravitational force
Force on m due to m1 is equal to the force on m due to m2.



3 - y = 1.87 y
3 = 2.87 y
y = 1.045 m
Thus, the net force on 51 kg is zero if it is placed at a distance of 1.045 m from 120 kg.
Answer:
A switch opens or closes the electrical circuit, turning the flow of electricity on or off.
Explanation:
To solve this problem it is necessary to apply the concepts related to the described wavelength through frequency and speed. Mathematically it can be expressed as:

Where,
Wavelength
f = Frequency
v = Velocity
Our values are given as,

Speed of sound
Keep in mind that we do not use the travel speed of the ambulance because we are in front of it. In case it approached or moved away we should use the concepts related to the Doppler effect:
Replacing we have,


Therefore the frequency that you hear if you are standing in from of the ambulance is 0.1214m
Explanation:
a) I = V / R
1.70 = 115 / R
R = 115 / 1.70
R = 67.647
R = 67.65 ohms
Therefore, equivalent resistance is 67.65 ohms
b) Equivalent resistance of circuit from above sum is 67.65 ohms
Given resistance of each bulb is 1.50 ohms
Number bulbs = Equivalent resistance / Resistance of each bulb
= 67.65 / 1.50
= 45