Answer:

Explanation:
First, we write the equations of motion for each axis. Since the crate is sliding with constant speed, its acceleration is zero. Then, we have:

Where T is the tension in the rope, F is the force exerted by the first worker, f_k is the frictional force, N is the normal force and mg is the weight of the crate.
Since
and
, we can rewrite the first equation as:

Now, we solve for
and calculate it:

This means that the crate's coefficient of kinetic friction on the floor is 0.18.
<span>It is measured in calories </span>
Answer:
(a) 
(b) 
(c) 
Explanation:
First change the units of the velocity, using these equivalents
and 

The angular acceleration
the time rate of change of the angular speed
according to:


Where
is the original velocity, in the case the velocity before starting the deceleration, and
is the final velocity, equal to zero because it has stopped.

b) To find the distance traveled in radians use the formula:


To change this result to inches, solve the angular displacement
for the distance traveled
(
is the radius).


c) The displacement is the difference between the original position and the final. But in every complete rotation of the rim, the point returns to its original position. so is needed to know how many rotations did the point in the 890.16 rad of distant traveled:

The real difference is in the 0.6667 (or 2/3) of the rotation. To find the distance between these positions imagine a triangle formed with the center of the blade (point C), the initial position (point A) and the final position (point B). The angle
is between the two sides known. Using the theorem of the cosine we can find the missing side of the the triangle(which is also the net displacement):


Momentum is a product mass and velocity. If a certain object posses a kinetic energy, then it should have a momentum since it is moving which has a velocity. However, if the object is at rest and only has potential energy, then it would not have momentum. So, for the first question the answer would be yes, an object can have energy without having any momentum. For the second question, every object whether it is moving or at rest, possess some energy, potential for an object at rest and kinetic for an object that is moving. Thus, the answer would be no, an object having momentum would always have energy.
<span>In transverse waves, particles of the medium vibrate to and from in a direction perpendicular to the direction of energy transport.</span>