Answer:
B) Friction
Explanation:
Friction is a force that acts when an object is sliding along a surface. Microscopically, this force is due to the fact that the two surfaces are not perfectly smooth, but they have "imperfections" that cause a force that opposes the motion of the object.
For an object sliding on a flat surface, the force of friction has magnitude:

where
is the coefficient of kinetic friction
m is the mass of the object
g is the acceleration of gravity
The direction of the force of friction is always opposite to the direction of motion of the object.
In reality, friction also acts if the object is at rest and it is pushed by a force; in this case, we talk about static friction, and its magnitude is

where
is called coefficient of static friction, and it is generally larger than the coefficient of kinetic friction.
Answer:
D. a person pulling a sled.
Explanation:
contact force only occurs when something directly comes in contact with another object.
a. is wrong because that is called magnetic force.
b. gravitational force
c. is an electrical force
Answer:
Force = 3.333 Newton
Explanation:
Given the following data;
Change in momentum = 10 Kgm/s
Time = 3 seconds
To find the force acting on it;
In Physics, the change in momentum of a physical object is equal to the impulse experienced by the physical object.
Mathematically, it is given by the formula;
Force * time = mass * change in velocity
Impulse = force * time
Substituting into the formula, we have;
10 = force * 3
Force = 10/3
Force = 3.333 Newton
Answer:
1.65
Explanation:
The equation of the forces along the horizontal direction is:
(1)
where
F = 65 N is the force applied with the push
is the frictional force
m = 4 kg is the mass
is the acceleration
The force of friction can be written as
(2), where
is the coefficient of kinetic friction
R is the normal force exerted by the floor
The equation of forces along the vertical direction is
(3)
since the bookcase is in equilibrium. Substituting (2) and (3) into (1), we find

And solving for
,

Kinematics : Study of motion
Fluid kinematics : study of how fluid flows and how to describe its motion.
There are two ways to describe fluid motion
one is Eulerian, where the variations are described at all fixed stations as a function of time.
the other is Lagrangian, in which one follows all fluid particles and describes the variations around each fluid particle along its trajectory.
<u>DIFFRENCE BETWEEN LAGRANGIAN AND EULERIAN:</u>
1.Both Lagrangian and Eulerian describes time variation.
2. Eulerian describes the rate of change in one point of space
Lagrangian descries rate of change of a property of material system.
To know more about the Lagrangian and Eulerian :\brainly.com/question/14944792
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