Conservation of Energy

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Questions and Answers

What is the fundamental principle of conservation of energy?

Energy can be both created and destroyed

Energy can neither be created nor destroyed, it only changes form (correct)

Energy can be destroyed but not created

Energy can be created but not destroyed

What is the unit of measurement for gravitational potential energy?

Newton

Meter

Kilogram

Joule (correct)

What is the formula to calculate gravitational potential energy?

mgh/2

mv^2

mgh (correct)

What is the purpose of the weighing scale in the physics lab?

To measure the mass of the toy car Signup and view all the answers

What is the dependent variable being measured in the physics lab?

The energy released as heat through friction Signup and view all the answers

What is the formula to calculate kinetic energy?

1/2 mv^2 Signup and view all the answers

What is the purpose of the inclined plane in the physics lab?

To investigate the conservation of energy Signup and view all the answers

What is the unit of measurement for the acceleration due to gravity?

Meter per second squared Signup and view all the answers

What type of energy is being converted to heat through friction in the physics lab?

Kinetic and gravitational potential energy Signup and view all the answers

What is the purpose of the stopwatch in the physics lab?

To measure the time it takes for the toy car to roll down the ramp Signup and view all the answers

What is the purpose of marking a starting point near the top of the ramp?

To measure the height of the starting point above the surface Signup and view all the answers

What is measured when the toy car reaches the bottom of the ramp?

The time it takes for the car to reach the stopping point Signup and view all the answers

What is the equation for kinetic energy?

Kinetic energy equals one half times mass times velocity squared Signup and view all the answers

What is the purpose of calculating the gravitational potential energy?

To compare it with the kinetic energy and identify energy loss Signup and view all the answers

What is little g equal to on Earth?

9.8 Signup and view all the answers

What is the purpose of finding the difference between the kinetic energy and gravitational potential energy?

To identify the energy loss due to friction Signup and view all the answers

What is the unit of measurement for kinetic energy and gravitational potential energy?

Joules Signup and view all the answers

What is the purpose of repeating the experiment at least five times?

To increase the accuracy of the results by finding the average Signup and view all the answers

What is the first step in analyzing the data?

Calculate the speed of the car at the bottom of the ramp Signup and view all the answers

What is the reason for the difference between the kinetic energy and gravitational potential energy?

Some energy is converted into heat due to friction Signup and view all the answers

Study Notes

Conservation of Energy

Energy exists in various forms, including kinetic energy (movement), elastic energy, and gravitational potential energy.
Conservation of energy principle states that energy is neither created nor destroyed; it only transforms between types.
When one energy type decreases, another type must increase.

Gravitational Potential Energy (GPE)

GPE is determined by an object's height above a surface.
Higher objects possess greater gravitational potential energy.
GPE formula: GPE = mgh
- m = mass in kilograms
- g = acceleration due to gravity (9.8 m/s² on Earth)
- h = height in meters

Kinetic Energy (KE)

Kinetic energy increases with an object's speed.
KE formula: KE = 1/2 mv²
- m = mass in kilograms
- v = velocity in meters per second

Physics Lab Overview

Objective: Investigate energy conservation using an inclined plane and measure heat loss via friction.

Required Materials

Ramp construction materials (plank of wood, stack of books)
Smooth flat surface
Stopwatch
Tape measure or ruler
Duct tape
Toy car
Weighing scale (grams or kilograms)

Lab Procedure Steps

Construct a ramp ensuring a smooth transition to the surface.
Mark starting and stopping points using duct tape, measuring distance and height.
Release the toy car from the starting point, timing its descent with a stopwatch.
Repeat the experiment at least five times, recording time for each trial.
Calculate the average time from all trials.
Measure the toy car's mass using the scale.

Data Analysis

Calculate the car's speed using the formula: Speed = Distance / Time.
Determine kinetic energy using the calculated speed and mass.
Calculate initial gravitational potential energy using the height and mass from the starting point.
Compare kinetic energy with gravitational potential energy: typically, KE should be less than GPE.
Determine the energy lost to heat through friction by finding the difference between GPE and KE.

Key Observations

Energy is conserved even when kinetic energy is lower than gravitational potential energy due to transformation into heat.
Energy loss through friction is a critical factor in experiments involving energy transformation.