# Finding kinetic energy from force, distance, mass

• nc1617
In summary, the conversation discusses a homework problem involving a rock being released from rest into a pond with a constant upward force of water resistance. The task is to calculate the nonconservative work done by water resistance, the gravitational potential energy, the kinetic energy, and the total mechanical energy at different depths below the water's surface. The equation for kinetic energy is mentioned and it is suggested to find the acceleration in order to solve the problem.
nc1617

## Homework Statement

A 1.85-kg rock is released from rest at the surface of a pond 1.00 m deep. As the rock falls, a constant upward force of 3.70 N is exerted on it by water resistance. Calculate the nonconservative work, Wnc, done by water resistance on the rock, the gravitational potential energy of the system, U, the kinetic energy of the rock, K, and the total mechanical energy of the system, E, for the following depths below the water's surface. Let y = 0 be at the bottom of the pond.

I need to find kinetic energy for three different distances, 0, .5, and 1.

## Homework Equations

Kinetic energy= 1/2mv^2

## The Attempt at a Solution

I understand the equation. however do not know how to get V. do i need to find acceleration and go from there? or is there a simpler method?

Yes, finding the acceleration would be a great place to start

## 1. How is kinetic energy calculated?

Kinetic energy is calculated by multiplying the mass of an object by the square of its velocity and dividing by 2. The formula is KE = 1/2 * m * v^2.

## 2. What units are used to measure kinetic energy?

Kinetic energy is measured in joules (J) in the International System of Units (SI). However, in some industries, it may also be measured in foot-pounds (ft-lb) or calories (cal).

## 3. Can kinetic energy be negative?

No, kinetic energy cannot be negative. It is a scalar quantity and is always positive or zero. Negative values may result from calculation errors or when considering potential energy.

## 4. How does an increase in force affect kinetic energy?

An increase in force applied to an object will result in an increase in its kinetic energy. This is because the force accelerates the object, increasing its velocity, which is directly proportional to kinetic energy.

## 5. What is the relationship between distance and kinetic energy?

The relationship between distance and kinetic energy is indirect. Increasing the distance an object travels will decrease its kinetic energy, assuming all other variables remain constant. This is because distance is directly proportional to velocity, which is squared in the kinetic energy formula.

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