Conservation of Energy
Power
Work
Energy
Work - Energy Theorem
100
Can Mechanical Energy ever change?
Why or why not?
Always constant , unless some energy is "lost" as heat
100
This is the equation and units for power.
What is
P=W/t = Fd/t
Measured in Watts
100
If Timmy pushes the cart with 6N across a 30m parking lot, how much work can he do?
180 Joules
100
What are the formulas for GPE, KE, & ME?
PE = mgh
KE =(0.5)(m)(v2)
ME (w/o) = GPE + KE
ME (w/) = GPE + KE + Heat
100
What are the two formulas you can use to solve for Work?
W = F x d
W = KE2 - KE1
200
DAILY DOUBLE: A bike rider approaches a hill at a speed of 3.5 m/s. He coasts up the hill as far as he can go. The mass of the bike and rider together is 77 kg. What will be the height when all of the kinetic energy is transferred to potential energy?
What is 0.62 m?
200
How much power can Jacky produce if she uses 15 seconds to do 178 J of work?
11.9 Watts
200
These are the equations and units for work.
Force x Distance = Work
Measured in Joules
200
What is the GPE of a 40 kg lion sitting atop a 65 m tree?
25,480 J
200
Potential and Kinetic Energy are directly proportional.
True or False?
False, inversely
300
If no other forms of energy besides kinetic and gravitational potential energy are present, then this equation represents mechanical energy.
What is ME = Ke + Pe
300
I toss a 5.0 kg football with 15 N of force across 18 meters in 3.0 seconds. How much power have I produced?
290 Watts
300
If Cristina does 40J of work over 25m, how much force does she use?
1.6 Newtons
300
As a skydiver falls to the earth, their ____ energy is converted into ____.
Draw the graphs that support this.
Gravitational Potential energy is converted into Kinetic energy.
300
This theorem states that energy can never be created or destroyed.
True or False?
False
400
What happens to energy between the Top of a hill and the Bottom of a hill?
If I roll down the hill, then...
If I walk up the hill, then...
Energy transforms from one form to another
PE --> KE
KE --> PE
400
If Sheena uses 6.00x10²N to push her daughter in the swing, her daughter will fly 0.910 m into the air in appx. 2.54 seconds. How much power must Sheena produce in order to accomplish this feat?
215 W
400
Hans Full is pulling on a rope to drag his backpack to school across the ice. He pulls rightwards with a force of 22.9 Newtons to drag his backpack a horizontal distance of 129 meters to the right. Determine the work done upon the backpack.
2,950 J
400
A 35kg bowling ball is dropped from a height of 150m. By the time the ball reaches 10m above the ground, it has a velocity of 15 m/s. Calculate the GPE at the top and the KE at the bottom of the building.
Top : GPE = 51,450 J
Bottom : KE =51,450 J
400
I've been pushing my 5 kg cart around the store at 19 m/s, but I'm tired. How much less work should I do to slow down to 10 m/s?
-652.5 J
500
A large chunk of ice with mass 12.0 kg falls from a roof 6.00 m above the ground. Ignoring air resistance, what is the kinetic energy of the ice when it reaches the ground?
What is 706 J?
500
A 1500 kg Honda is accelerating at 175 m/s² down a lonely, dark, 150 m back road. It crashes into a brick building 12 seconds later. How much power did the car produce?
3,281,250 Watts
500
During the Powerhouse lab, Jerome runs up the stairs, elevating his 102 kg body a vertical distance of 2.29 meters. How much work does he do?
2290 J
500
DAILY DOUBLE - Defend answer with work for points
Out of the following examples, this one has the greatest kinetic energy: a 35.0-g bullet traveling at 1.20×103 m/s, a 35.0-kg cheetah running at 30 m/s, an 875-kg car traveling at 5 m/s, or a 148-g pitched baseball moving at 45 m/s?
What is the bullet?
500
What does the work-energy theorem state?
WORK DONE = ENERGY GAINED
OR
When work is done, energy is transferred from one form to another