In Example 10.2, if the angle θ = 82.0°, how much work is done by you, in Joule? Your answer needs to have 2 significant figures, including the negative sign in your answer if needed. Do not include the positive sign if the answer is positive. No unit is needed in your answer, it is already given in the question statement.
Kinematics
A machine is a device that accepts energy in some available form and utilizes it to do a type of work. Energy, work, or power has to be transferred from one mechanical part to another to run a machine. While the transfer of energy between two machine parts, those two parts experience a relative motion with each other. Studying such relative motions is termed kinematics.
Kinetic Energy and Work-Energy Theorem
In physics, work is the product of the net force in direction of the displacement and the magnitude of this displacement or it can also be defined as the energy transfer of an object when it is moved for a distance due to the forces acting on it in the direction of displacement and perpendicular to the displacement which is called the normal force. Energy is the capacity of any object doing work. The SI unit of work is joule and energy is Joule. This principle follows the second law of Newton's law of motion where the net force causes the acceleration of an object. The force of gravity which is downward force and the normal force acting on an object which is perpendicular to the object are equal in magnitude but opposite to the direction, so while determining the net force, these two components cancel out. The net force is the horizontal component of the force and in our explanation, we consider everything as frictionless surface since friction should also be calculated while called the work-energy component of the object. The two most basics of energy classification are potential energy and kinetic energy. There are various kinds of kinetic energy like chemical, mechanical, thermal, nuclear, electrical, radiant energy, and so on. The work is done when there is a change in energy and it mainly depends on the application of force and movement of the object. Let us say how much work is needed to lift a 5kg ball 5m high. Work is mathematically represented as Force ×Displacement. So it will be 5kg times the gravitational constant on earth and the distance moved by the object. Wnet=Fnet times Displacement.
In Example 10.2, if the angle θ = 82.0°, how much work is done by you, in Joule?
Your answer needs to have 2 significant figures, including the negative sign in your answer if needed. Do not include the positive sign if the answer is positive. No unit is needed in your answer, it is already given in the question statement.
![10.2 Work Done in Pulling a Suitcase
It's 120 m from one gate to another in the airport. You use a strap inclined upward at a 45° angle to pull your suitcase
through the airport. The tension in the strap is 20 N. How much work do you do?
STRATEGIZE Let's take the system to be the suitcase + floor. As with the dog sled, friction forces (in the wheels or
between the wheels and the floor) are internal forces. Both the strap and you are forces outside the system. The
tension force of the strap does work on the suitcase as it rolls. Since you are the one pulling the strap, this is,
ultimately, energy provided by you.
PREPARE Figure 10.8 O is a before-and-after visual overview showing the suitcase and the strap. The force is at an
angle to the displacement, so we must use Equation 10.6 O to calculate the work.
FIGURE 10.8 A suitcase pulled by a strap.
Before:
After:
Known
T- 30 N
6= 45°
d=120m
Eind
SOLVE The tension force does work
W = Td cos 0 = (20 N)(120 m) cos(45°) = 1700 J](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fe3f7e491-c7d7-4138-8e12-ab326d0d2810%2F935196fa-e345-47a8-802b-61ba84683e77%2Fcox91wu_processed.png&w=3840&q=75)
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