1. A 6.2kg box is moving at 2.4m/s to the left. a) What is its kinetic energy? 2.4m/s 6.2kg b) How fast will the box be moving after friction does W = - 4J of work on it?
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.
![# Physics Problem: Kinetic Energy and Work Done by Friction
## Problem Statement
**1.** A 6.2 kg box is moving at 2.4 m/s to the left.
**a)** What is its kinetic energy?
**b)** How fast will the box be moving after friction does \( W = -4 \, \text{J} \) of work on it?
## Diagram Explanation
The diagram depicts a box with a mass of 6.2 kg. The box is shown to be moving to the left with a velocity of 2.4 m/s. An arrow indicates the direction of movement to the left, and the velocity is labeled next to it. The mass of the box is indicated below it.
## Concepts Covered
This problem requires understanding of the following physics concepts:
- **Kinetic Energy:** The energy possessed by an object due to its motion, calculated with the formula:
\[
\text{Kinetic Energy (KE)} = \frac{1}{2} m v^2
\]
where \( m \) is the mass and \( v \) is the velocity of the object.
- **Work-Energy Principle:** The change in kinetic energy of an object is equal to the net work done on the object. When friction does \( W = -4 \, \text{J} \) of work, it reduces the kinetic energy of the box. This can be summed up as:
\[
\Delta KE = W
\]
Use these formulas and concepts to solve the problem and determine the velocity of the box after the work done by friction.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Ff9150cb0-c0bc-425f-af9e-d612c3f65210%2F35129564-d734-4ce9-961e-7b687593050e%2F8qo3nlk_processed.jpeg&w=3840&q=75)
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