Answer:
1) A downward force of magnitude 5 N is exerted on the book by the force of of gravity
2) An upward force of magnitude 5 N is exerted on the book by the table
Explanation:
First of all, any object near the Earth's surface experiences the forces of gravity, which is also called weight of the object. This force always acts downward.
For the book in the problem, the magnitude of the weight is 5 N.
We also know that the book is at rest: this means that the net force acting on it is zero, and there must be another force balancing the weight, in order to give a zero net force. This other force is the reaction force exerted by the table on the book: the magnitude of this force must be equal to the force of gravity (so, 5 N) and its direction is opposite to the weight, therefore upward.
Newton’s 2nd law states that Force is equal to
the product of mass (m) and acceleration (a):
F = m a --->
1
While in magnetic forces, force can also be expressed as:
F = q v B --->
2
where,
q = total charge
v = velocity = 45 cm / s = 0.45 m / s
B = the magnetic field = 85 T
First we solve for the total charge, q:
q = 3.8 × 10^-23 g (1 mol / 23 g) (6.022 × 10^23 electrons / mol) (1.602 ×
10^-19 C / electron)
q = 1.594 × 10^-19 C
We equate equations 1 and 2 then solve for acceleration a:
m a = q v B
a = q v B / m
a = [1.594 × 10^-19 C * 0.45 m / s * 85 T] / 3.8 × 10-26 kg
a = 160,437,862.2 m/s^2
Therefore the maximum acceleration of Na ions is about 160 × 10^6 m/s^2.
