Answer:
The balanced equation is 3NaBr+1H3PO4 ----> 1Na3PO4 + 3HBr
This is a double replacement because you are switching both the Na and the Hydrogen.
Explanation:
I believe the answer is D
Answer:
(a) 
(b) 
Explanation:
Parameter given:
Electric field, E = 
(a) Electric force is given (in terms of electric field) as a product of electric charge and electric field.
Mathematically:

Electric charge, q, of an electron = 

(b) This electrostatic force causes the electron to accelerate with an equivalent force:
F = -ma
where m = mass of an electron
a = acceleration of electron
(Note: the force is negative cos the direction of the force is opposite the direction of the electron)
Therefore:

Mass, m, of an electron = 
=> 
The acceleration of the electron is 
Diameter = 60 cm, Radius = 60/2 = 30 cm = 30/100 = 0.3 m.
The pebble in the tread goes by 3 times every second.
This is the same as 3 times per second.
Recall the unit of frequency is Hertz or per second, s⁻¹
So 3 times per second, Frequency, f = 3s⁻¹ or 3 Hertz
For angular motion:
Angular speed, ω = 2πf
= 2*π*3
= 6π rad/s
Linear speed, v = ωr = 6π * 0.3 = 1.8π m/s
Linear acceleration, a = v² / r
a = 1.8π * 1.8π / 0.3 = 10.8π² m/s²
Angular acceleration α = a/r = 10.8π² / 0.3 = 36π² rad/s²
Angular speed = 6π rad/s ≈ 18.840 rad/s
The linear speed of the pebble = 1.8π m/s ≈ 5.655 m/s
The angular acceleration = 36π² rad/s² ≈ 355.306 rad/s²
The linear acceleration of the pebble = 10.8π² m/s ≈ 106.592 m/s²