# Work and Kinetic Energy and speed

• mohd22
In summary, the conversation discusses the relationship between kinetic energy and work done on an object, specifically in the context of a sled starting from rest. It also mentions using quantitative analysis to find the net force and net work on the sled.
mohd22
The kinetic energy K of an object of mass m moving at a speed v is defined as K=(1/2)mv2. It seems reasonable to say that the speed of an object--and, therefore, its kinetic energy--can be changed by performing work on the object. In this problem, we will explore the mathematical relationship between the work done on an object and the change in the kinetic energy of that object.

Let us now consider the situation quantitatively. Let the mass of the sled be m and the magnitude of the net force acting on the sled be Fnet. The sled starts from rest.

Consider an interval of time during which the sled covers a distance s and the speed of the sled increases from v1 to v2. We will use this information to find the relationship between the work done by the net force (otherwise known as the net work) and the change in the kinetic energy of the sled.

1.Find the net force Fnet acting on the sled.?
(Express your answer in terms of some or all of the variables m, s, v1, and v2)
2.Find the net work Wnet done on the sled.?
(Express your answer in terms of some or all of the variables Fnet and s.)

Last edited:
If you're expecting a response on these two posts, you should read the rules above. You need to make an effort to solve the problem before asking for help.

## 1. What is work and how is it related to kinetic energy?

Work is defined as the force applied to an object multiplied by the distance the object moves in the direction of the force. In other words, work is the energy transferred to an object to move it a certain distance. Kinetic energy, on the other hand, is the energy an object possesses due to its motion. Work and kinetic energy are related in that work is the cause of a change in an object's kinetic energy.

## 2. How is work calculated?

Work is calculated by multiplying the force applied to an object by the distance the object moves in the direction of the force. The formula for work is W = Fd, where W is work, F is force, and d is distance.

## 3. What is the relationship between work and speed?

The relationship between work and speed is that the amount of work done on an object is directly proportional to its speed. This means that the faster an object moves, the more work is required to change its speed.

## 4. How do you calculate the speed of an object?

The speed of an object can be calculated by dividing the distance traveled by the time it took to travel that distance. The formula for speed is v = d/t, where v is speed, d is distance, and t is time.

## 5. How is kinetic energy related to speed?

Kinetic energy is directly proportional to speed. This means that as an object's speed increases, its kinetic energy also increases. The formula for kinetic energy is KE = 1/2mv^2, where KE is kinetic energy, m is mass, and v is speed.

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