Answer:
A. False
B. False
C. True
D. True
E. True
F. True
Explanation:
A. The equation Ax=b is referred to as a matrix equation and not vector equation.
B. If the augmented matrix [ A b ] has a pivot position in every row then equation Ax=b may or may not be consistent. It is inconsistent if [A b] has a pivot in the last column b and it is consistent if the matrix A has a pivot in every row.
C. In the product of Ax also called the dot product the first entry is a sum of products. For example the the product of Ax where A has [a11 a12 a13] in the first entry of each column and the corresponding entries in x are [x1 x2 x3] then the first entry in the product is the sum of products i.e. a11x1 + a12x2 +a13x3
D. If the columns of mxn matrix A span R^m, this states that every possible vector b in R^m is a linear combination of the columns which makes the equation consistent. So the equation Ax=b has at least one solution for each b in R^m.
E. It is stated that a vector equation x1a1 + x2a2 + x3a3 + ... + xnan = b has the same solution set as that of the linear system with augmented matrix [a1 a2 ... an b]. So the solution set of linear system whose augmented matrix is [a1 a2 a3 b] is the same as solution set of Ax=b if A=[a1 a2 a3] and b can be produced by linear combination of a1 a2 a3 iff the solution of linear system corresponding to [a1 a2 a3 b] takes place.
F. It is true because lets say b is a vector in R^m which is not in the span of the columns. b cannot be obtained for some x which belongs to R^m as b = Ax. So Ax=b is inconsistent for some b in R^m and has no solution.
The force of friction is equal to the pushing force, and the acceleration is zero
Explanation:
In this problem, we are pushing a piano along the floor, in the horizontal direction.
There are 2 forces acting in the horizontal direction on the piano:
- The applied force,
, acting forward - The force of friction,
, acting backward
Therefore, the net force in the horizontal direction is

According to Newton's second law, the net force is equal to the product between the piano's mass (m) and its acceleration:

Combining the two equations,

However, we are also told that the piano moves at constant speed, therefore the acceleration is zero:

And so,

which means that the force of friction is equal to the applied force.
Learn more about Newton's second law:
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Answer:
w = 706.32 [N]
Explanation:
The force due to gravitational acceleration can be calculated by means of the product of mass by gravitational acceleration.
w = m*g
where:
w = weight [N] (units of Newtons)
m = mass = 72 [kg]
g = gravity acceleration = 9.81 [m/s²]
Then we have:
![w = 72*9.81\\w = 706.32 [N]](https://tex.z-dn.net/?f=w%20%3D%2072%2A9.81%5C%5Cw%20%3D%20706.32%20%5BN%5D)
Answer:
Current, I = 1.08 A
Explanation:
Given that,
Length of the copper wire, l = 12 cm = 0.12 m
Mass of the wire, m = 16 g = 0.016 kg
Magnetic field, B = 1.2 T
The magnetic field is oriented perpendicular to the wire. We need to find the current in the wire.
Magnetic force, F = BIL
Force of gravity, F' = mg
F' = F



I = 1.08 A
So, the current through the wire is 1.08 A. Hence, this is the required solution.