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:
C
Explanation:
Angular momentum is the product of moment of inertia and angular velocity.
L = I × ω
Since the planet follows a stable circular orbit, I and ω are constant and non-zero. Therefore, the angular momentum is constant and non-zero.
Answer:
Magnitude of static friction force is 70 sin40° = 44.99 N.
No, it is not necessary that it is maximum static friction.
Normal force is equal to 70 cos40° = 53.62 N.
Explanation:
We apply newton law of moton equation along the plane and perpendicular to plane;
Along the plane,
70 sin 40° =
---------------(1)
70 cos 40° = N --------------(2)
= μN -----------------(3)
So, it depends on the value of μ that the friction is maximum or not .
Answer:
A 300-kg crate is placed on a adjustable incline plane. as one end of the incline is raised, the crate begins to move downward. if the crate slides down the plane with the acceleration of .70 m/s2 , when the incline is 25 degrees, what is the coefficient of kinetic friction between ramp and crate?
Explanation: