Physics Lesson 14
Tarzan steps out of his house and grabs a hanging vine to swing to the ground. If his house is 11.3 m above the ground, what is Tarzan's speed when he reaches the ground? Assume that there is no friction, and that Tarzan has a mass of 105 kg.
14.9 m/s
Which of the following formulas implies that mechanical energy is conserved?
MEi=MEf initial mechanical energy=final mechanical energy
Two pinewood derby (wooden) cars are racing down a frictionless ramp. Their wheels are also frictionless. One weighs 5.0 ounces; the other weighs 4.5 ounces. Neglecting air resistance, which will reach the end of the ramp first?nical energy is always equal to
They will reach at the same time
Which of the following is a true statement about the conservation of energy?
Total Energy is Conserved
One definition of energy is the abiilty to
do work
The potential energy of mechanical energy can be either
elastic or gravitational
In physics, to say that energy is conserved means that
energy is not lost nor gained in the process.
In a pendulum, at its height, all mechanical energy is gravitational potential energy, and is equal to mgh. At the bottom of its swing, all energy is kinetic and is expressed at 0.5mv2. If mechanical energy is conserved, which of the following equations applies?
gh=0.5v^2
What are the two forms of potential energy that can be included in the equation for mechanical energy? ...∑PE...
gravitational and elastic
When you rub your hands together vigorously, the kinetic energy of your hand movement is converted mostly into
heat
When a pendulum, roller coaster, or any other body that goes up and down, ascends to its maximum height, then begins to descend, its energy _________________.
is being converted mainly from potential to kinetic energy
The two components of mechanical energy are
kinetic and potential energy
Friction converts kinetic energy to
potential energy
Which of the following situations does NOT largely conserve mechanical energy?
sanding a block of wood
mechanical energy
the amount of work an object can do because of the object's kinetic and potential energies
In situations where mechanical energy is conserved, the mechanical energy is always equal to
the sum of potential energy and kinetic energy
