Work
What is the formula for work?
W = Fd work = force times displacement
What is definition of power?
The rate at which work is done. Work over time
What type of energy is associated with a compressed or stretched object?
Elastic potential energy
What simple machine is used to pry a nail from a board?
Lever
Friction converts kinetic energy to what?
Thermal Energy
Give an example of work using the scientific definition.
Any answer with force and displacement.
More powerful motors can do what?
A. move work in a longer time
B. same work in a shorter time
C. less work in a longer time
D. same work in a longer time
B. Same work in a shorter time
Which one of the following three energies is NOT involved in hitting a tennis ball?
kinetic energy
chemical potential energy
elastic potential energy
Chemical potential energy
Where should you push a door to apply the most torque when opening the door?
Far from the hinges.
What is always conserved in the conservation of energy?
Total Energy: The forms change but the total stays the same.
What is the definition of work?
Force over a displacement
What is the SI unit for power?
W watts
What energy is associated with an object in motion?
Kinetic Energy
Potential Energy
Kinetic Energy
Mass
Length
Mechanical Energy
Mechanical Energy and Mass
Give an example of work used in the everyday sense of the word.
Any answer that doesn't deal with force and displacement
What is the SI units for Joules?
A 100 W light bulb can:
A. convert 100J of kinetic energy to potential energy each second
B. Converts 100 J of potential energy to kinetic energy each second
C. Converts 100 J of mechanical energy to nonmechanical energy each second
D. Converts 100 J of electrical energy to other forms of energy each second
D. Converts 100 J of electrical energy to other forms of energy each second
Which form of energy is involved in weighing fruit on a spring scale?
Elastic Potential Energy
Suppose a doorknob is placed in the center of the door. Compared to a door whose know is located at the edge, describe the force need to the door with the doorknob in the center compared to on the edge.
Twice as much force once it is only half the distance.
Is work being done if a car decelerates while traveling on a flat stretch of road?
Yes the deceleration is a force slowing the car down and it is moving causing a displacement. Work is being done.
If a machine increases the distance over which work is done. What happens to the force?
Less force is need.
What is the equation for power?
P = w/t
A tennis ball is thrown up into the air, reaches its peak height, then returns to the ground. Describe the energy transfer that takes place during the flight of the ball? Is energy conserved?
Lots of kinetic energy to start then lots of potential energy at the top. In the end when it is fall it turns from potential energy to kinetic energy. Mechanical energy is conserved the whole time.
What is mechanical advantage and what is the equation?
Mechanical advantage: ability to do more work with a machine then you could without it.
Equation: Work out/Work in
What is the equation for kinetic energy of a spring?
KE = 1/2 m v2