Answer:
a) C.M 
b) 
Explanation:
The center of mass "represent the unique point in an object or system which can be used to describe the system's response to external forces and torques"
The center of mass on a two dimensional plane is defined with the following formulas:


Where M represent the sum of all the masses on the system.
And the center of mass C.M 
Part a
represent the masses.
represent the coordinates for the masses with the units on meters.
So we have everything in order to find the center of mass, if we begin with the x coordinate we have:


C.M 
Part b
For this case we have an additional mass
and we know that the resulting new center of mass it at the origin C.M
and we want to find the location for this new particle. Let the coordinates for this new particle given by (a,b)

If we solve for a we got:




And solving for b we got:

So the coordinates for this new particle are:

Answer: - 25.2 kgm/s
Explanation: The mass of the ball is 0.5kg, and the initial velocity = 10.6m/s.
The final velocity is in opposite direction of the initial hence final velocity (v) = - 19.9 m/s
Impulse = change in momentum = final momentum - initial momentum.
Final momentum = mass × final velocity
Final momentum = - 19.9 × 0.5
Final momentum = - 9.95 kgm/s
Initial momentum = mass × initial velocity
Initial momentum = 0.5 × 10.6 = 5.3kgm/s
Change in momentum = final momentum - initial momentum = - 19.9 - 5.3
Change in momentum = - 25.2 kgm/s
The negative sign implies that the change in momentum is the opposite direction relative to the first.
Explanation:
Density is measured in kg⋅m−2 . This means that it is derived from fundamental units which are the kilogram and metre.