It means that they were set earlier therefor they are older.
Answer:
Electric force, 
Explanation:
It is given that,
Charge on an electron is 
Electric field, 
We need to find the magnitude of the electric force on this electron due to this field. The electric force is given by :

So, the electric force is
.
Answer:
2.01
Explanation:
First, we need to find the centripetal acceleration.
We're given that the merry go round rotates 1 revolution in 2.09 seconds. Converting to rpm, we know that it rotates 30 revolution per minute
Now this speed gotten in rpm will be converted to m/s, to ease the calculation
30 rpm = πdN/60 m/s
30 rpm = (3.142 * 4 * 30)/60
30 rpm = 377.04/60
30 rpm = 6.284 m/s
a(c) = v²/r
a(c) = 6.284²/2
a(c) = 39.49 / 2
a(c) = 19.74 m/s²
F = ma
F = 50 * 19.74
F = 987 N
Also, Normal Force, F(n) =
F(n) = mg
F(n) = 50 * 9.81
F(n) = 490.5
We then use this to find the coefficient of static friction, μ
μ = F/F(n)
μ = 987 / 490.5
μ = 2.01