Potential Energy
In a system consisting of a ball and the Earth, what happens to the potential energy as the ball is lifted higher?
It increases.
What are the two main factors that determine how much kinetic energy a moving object has?
Mass and Velocity (speed)
A bowling ball sitting still on a high shelf is an example of what type of energy?
Gravitational Potential Energy.
When a moving pendulum reaches the bottom of its swing, most of its potential energy has turned into what?
Kinetic energy
What is the mathematical formula used to calculate Kinetic Energy?
KE = 1/2 m v2
Give me three types of potential energy
gravitational PE, Elastic PE, Chemical PE and Magentic PE
If you double the mass of a moving object but keep its speed the same, what happens to its kinetic energy?
It doubles
Between a parked semi-truck and a moving bicycle, which one has kinetic energy?
When two marbles collide, some kinetic energy is "lost" to the room. What two forms does that energy usually turn into?
Sound and Heat (Thermal energy).
What is the formula used to calculate Gravitational Potential Energy?
PE = mgh (mass x gravity x hieght)
If two hikers are at the top of the same mountain, but one hiker has a much heavier backpack, which hiker has more potential energy?
The hiker with the heavier backpack (more mass).
Which factor has a greater effect on kinetic energy: doubling the mass or doubling the speed?
Doubling the speed (because it is squared).
Which has more potential energy: A 10kg weight 5 meters in the air, or a 10kg weight 10 meters in the air?
10kg weight 10 meters in the air
According to the Law of Conservation of Energy, what happens to the total amount of energy in a system when it changes forms?
It stays the same (Energy is not created or destroyed).
Calculate the Kinetic Energy of a 2 kg ball moving at a speed of 4 m/s.
16 Joules (0.5 x 2 x 42) - No unit no points
To increase the potential energy of an object without changing its mass, what must you change?
Its height.
If a car triples its speed, how many times more kinetic energy does it have?
9 times more (32)
A baseball flying through the air after being hit by a bat. Write four different energies involved?
PE to raise the bat
KE to swing the bat
Transfer of KE to the ball
Thermal Energy at the point of contact
Sound Energy at the point of contact.
If a moving car hits a parked car and both start moving, what happened to the first car's kinetic energy?
It was transferred to the second car. (must include the word transfered)
A 5 kg box is sitting on a shelf 3 meters high. Calculate the Potential Energy of the system.Give the whole answer, do not round
147.15 Joules (5 x 3 x 9.81)
When an object falls, what happens to the potential energy in the system?
On a graph showing the relationship between speed and kinetic energy, why is the line a curve instead of a straight line?
Because energy increases exponentially (by the square) as speed increases.
Imagine a roller coaster car at the very top of the first hill. Describe its energy levels
High Potential Energy and zero (or very low) Kinetic Energy.
Explain why a bouncing ball never bounces back up to its original starting height.
Some energy is transformed into heat and sound during each bounce.
If an object has 100 Joules of Kinetic Energy and its speed doubles, what will its new Kinetic Energy be?
400 Joules (Because doubling speed quadruples the energy).