Science 8 Ch 9 Sec 3-4

mechanical energy

an object's combined kinetic energy and potential energy.

What factors affect an object's kinetic energy?

mass and speed

gravitational potential energy

potential energy related to an object's height

What are the three ways that an object can accelerate?

speeding up, slowing down, or changing direction.

law of conservation of energy

state that when one form of energy is transformed into another, no energy is destroyed in the process.

potential energy

stored energy that results fro the position or shape of an object is called this.

Energy

the ability to do work or cause chance is called energy

kinetic energy

the energy an object has due to its motion is called this.

elastic potential energy

the potential energy of objects that can be stretched or compressed.

What factors affect an object's potential energy?

weight and height relative to a reference point

Work

is done when an object is caused to move a certain distance.

acceleration

is the rate at which velocity changes with time.

How do you calculate acceleration?

Acceleration= final velocity minus initial velocity divided by time

Describe how a baseball player accelerates as he runs around the bases after hitting a home run.

Initially, he accelerates away from home plate. Upon reaching each base, the player accelerates by changing direction. The player accelerates again when slowing down after reaching home plate.

What unit of measurement is in kinetic energy?

Joules

Describe the energy transformations that occur when you bounce a ball.

Kinetic energy increases and potential energy decreases as the ball falls.

What is the formula for finding kinetic energy?

Kinetic energy= one half x Mass x Speed squared

What is the formula for mechanical energy?

Mechanical Energy= Kinetic energy + Potential Energy

Describe the motion of an object if its speed-versus-time graph is a horizontal line.

Such a graph means that the object is moving at a constant rate or stationary.

An ice skater glides around an ice rink at a constant speed of 2m/s. Is the skater accelerating? Explain

Yes the skater is accelerating by continually changing direction.

What type of graph can you use to analyze the acceleration of an object?

You can use a speed-versus-time graph or a distance-versus-time graph.