Question 1 According to the Law of Conservation of Energy, why does the first hill on a roller coaster always have to be the tallest of all the other hills?

Question 2
A single marble is placed at the top of a hill. The initial potential energy of the marble is 550 J. The marble slides down the hill. You take a picture of the marble at some point as it is down the hill. Without knowing the speed, the mass or the position of the marble, which of the following could be the only possible correct energies of the marble at this point? Assume no friction

a
Potential Energy = 310 J, Kinetic Energy = 180 J
b
Potential Energy = 140 J, Kinetic Energy 450 J
c
Potential Energy = 290 J, Kinetic Energy = 260 J
d
Potential Energy = 210 J, Kinetic Energy = 305 J

Question 3
What is the significance of the acceleration value, 9.8 m/s^2?

a
That is the acceleration due to the gravitational field of the Sun
b
That is the acceleration due to the gravitational field of the Earth
c
That is the acceleration due to the magnetic field of the Earth
d
That is the acceleration due to the charged particles of the Sun

Question 4
How can you prove that the potential energy of a stretched spring turns into kinetic energy when you release the spring?

Question 5
Under conditions of conservation of energy where the initial energy object is only gravitational potential energy and the final energy is only kinetic, write an equation to calculate the final velocity of the object. Ignore all friction. Show all work

Question 6
In which of the following situations would there be initial energy in the system?

a
An apple sits motionless on the ground near a tree
b
A spring is compressed and held at compression by a person before releasing it
c
A bowstring is neither pulled nor stretched on a bow
d
An object rests at a velocity of 0 on a flat surface at ground level

Question 7
Which of the following would be an example of mechanical energy?

a
Elastic Energy, Kinetic Energy, Gravitational Potential Energy
b
Gravitational Potential Energy, Thermal Energy
c
Electric Potential Energy, Nuclear Energy, Kinetic Energy
d
Magnetic Energy, Elastic Potential Energy

Question 8
A spring with a mass attached to it is stretched from the rest position of 20 cm to the position of 87 cm. If the spring constant of this spring is 1729 N/m, what is the potential energy stored in this spring?

a
561.29 J
b
120.97 J
c
388.07 J
d
254.79 J

Question 9
One of the major differences between our common Physics models of energy change and realistic models of them is:

a
In the Physics models, the acceleration due to gravity is rounded to a non-exact but easier to use number
b
In the Physics models, the velocities are only calculated at set intervals of time, instead of continuously
c
In the Physics models, the objects are assumed to have simplified shapes in order to make motion by acceleration easier to calculate
d
In the Physics models, we do not take into account the energy change by the friction of moving components

Question 10
What is terminal velocity?

a
A condition that only exists in an airless vacuum
b
The velocity needed to break the gravitational pull of the Earth
c
The kinetic energy of an object dropped from the highest point it can be dropped
d
The maximum speed an object can fall in the presence of air resistance

Question 11
Which of the following best defines the First Law of Thermodynamics?

a
The total kinetic energy of an object must be equal to the initial potential energy of that object and system
b
In order to change the internal energy of a system, you must either apply heat to the system, take heat out of the system, have work done on the system, or have the system do work
c
The total net force acting on an object is equal to the multiple of the mass of the object and the acceleration of that object
d
The total amount of disorder in a system can never decrease unless excess energy in the form of work is done on the system

Question 12
Name two of the four common boundry conditions we set when disucssing gravitational potential energy?

Question 13
According to Law of Conservation of Energy, if you calculate the sum total of all final energies in a system, which of the following should be true:

a
The sum total of all final energies in a system should be exactly equal to the sum total of all initial energies in a system
b
The sum total of all final energies in a system will be different depending on whether you count friction or not
c
The amount of the initial energies influences, but does not determine, the amount of final energies in a system
d
The initial amount of energy is a system must be provided by potential energy, not kinetic or thermal

Question 14
An object with a mass of 32 kg has an initial energy of 500 J. At the end of the experiment, the velocity of the object is recorded as 5.1 m/s. If the object travelled 50 m to get to this point, what was the average force of friction on object during the trip? Assume no potential energy. Show all work