In the figure the coefficient of static friction between mass (MA) and the table is 0.40, whereas the coefficient of kinetic friction is 0.28 ?

part a) What minimum value of (MA) will keep the system from starting to move?

part b) What value of(MA) will keep the system moving at constant speed?

Block on the table m(A) = m1,

block on the cord m2,
the coefficient of static friction is k1=0.4,
the coefficient of kinetic friction is k2 =0.28
(a)
Block A:
T = F(fr) = k1 •N = k(s) • m1 •g,
Block B: T = m2•g.
k1 • m1 •g= m2•g,
m1 = m2/k(s) = m2/0.4.

(b)
Block A:
T = F(fr) = k2 •N = k2 • m1 •g,
Block B:
T = m2•g.
k2• m1 •g= m2•g,
m1 = m2/k2 = m2/0.28.

To find the minimum value of MA that will keep the system from starting to move, and the value of MA that will keep the system moving at a constant speed, we need to use the concept of frictional forces.

First, let's understand the difference between static and kinetic friction:

- Static friction occurs when two surfaces are in contact but not moving relative to each other.
- Kinetic friction occurs when two surfaces are in contact and moving relative to each other.

Now let's solve each part of the question individually:

Part a) What minimum value of MA will keep the system from starting to move?

To keep the system from starting to move, the force of static friction between the mass MA and the table needs to equal the applied force on the mass. The formula for static friction is:

fs = µs * N

where fs is the force of static friction, µs is the coefficient of static friction, and N is the normal force between the two surfaces.

In this case, the normal force N is equal to the weight of the mass MA, so we can rewrite the formula as:

fs = µs * MA * g

where g is the acceleration due to gravity.

The minimum value of MA that will keep the system from starting to move occurs when the force of static friction fs is equal to the applied force.

So, to find the minimum value of MA:

1. Set up the equation:
µs * MA * g = applied force

2. Substitute the given values:
0.40 * MA * g = applied force

3. Solve for MA:
MA = applied force / (0.40 * g)

Part b) What value of MA will keep the system moving at constant speed?

When the system is moving at constant speed, the force of kinetic friction between the mass MA and the table is equal to the applied force. The formula for kinetic friction is:

fk = µk * N

where fk is the force of kinetic friction, µk is the coefficient of kinetic friction, and N is the normal force between the two surfaces.

In our case, the normal force N is equal to the weight of the mass MA, so we can rewrite the formula as:

fk = µk * MA * g

To keep the system moving at constant speed, the applied force needs to be equal to the force of kinetic friction.

So, to find the value of MA that will keep the system moving at constant speed:

1. Set up the equation:
µk * MA * g = applied force

2. Substitute the given values:
0.28 * MA * g = applied force

3. Solve for MA:
MA = applied force / (0.28 * g)

Note: In both parts, the applied force is not given in the question, so you would need to know the specific value of the applied force to calculate the corresponding minimum value of MA or the value of MA for constant speed.