Answer:
a) 
b) x = 4.47 cm
c) 
d) x = 1.48 cm
Explanation:
a) The center of mass is equal to:

Where m is the mass of beads and x is the distances, if x₁ = d₁, x₂ = d₂ and x₃ = d₃

b) If
m₁ = 23g
m₂ = 15 g
m₃ = 58 g
d₁ = 1.1 cm
d₂ = 1.9 cm
d₃ = 3.2 cm

c) The center of the mass of the beads realtive to the center of bead is:

d) 
Answer:
Yes it does.
Explanation:
"The North Magnetic Pole moves over time due to magnetic changes in Earth's core.
" - Wikipedia.
It does move around as the magnetic north does.
Answer: W =
J
Explanation: Since the potassium ion is at the outside membrane of a cell and the potential here is lower than the potential inside the cell, the transport will need work to happen.
The work to transport an ion from a lower potential side to a higher potential side is calculated by

q is charge;
ΔV is the potential difference;
Potassium ion has +1 charge, which means:
p =
C
To determine work in joules, potential has to be in Volts, so:

Then, work is


To move a potassium ion from the exterior to the interior of the cell, it is required
J of energy.
Answer:
The car stops in 7.78s and does not spare the child.
Explanation:
In order to know if the car stops before the distance to the child, you take into account the following equation:
(1)
vo: initial speed of the car = 45km/h
a: deceleration of the car = 2 m/s^2
t: time
xo: initial distance to the child = 25m
x: final distance to the child = 0m
It is necessary that the solution of the equation (1) for time t are real.
You first convert the initial speed to m/s, then replace the values of the parameters and solve the quadratic polynomial for t:


You take the first value t1 because it has physical meaning.
The solution for t is real, then, the car stops in 7.78s and does not spare the child.
On Earth, the acceleration of gravity is 9.8 m/s² downward.
So any object with only gravity acting on it gains 9.8 m/s of
downward speed every second.
If the rock starts out moving upward at 10 m/s, then it will
continue upward for only (10/9.8) = 1.02 second, before
it stops rising and starts falling.
Its average speed during that time is (1/2) (10 + 0) = 5 m/s .
At an average speed of 5 m/s for 1.02 sec,
the rock rises
(5 m/s) x (1.02 sec) = 5.102 meters .