Work, Power, and Machines
The transfer of energy to an object by the application of a force that causes the object to move in the direction of the force is...
What is work
One of the six basic types of machines, which are the basis for all other forms of machines is called a...
What is simple machine
The capacity to do work is...
What is energy
____ readily changes from one form to another.
What is energy
How much work is done by a person who uses a horizontal force of 25 N to move a desk 5.0 m?
W = Fd = (25 N)(5.0 m) = 125 J
A quantity that measures the rate at which work is done or energy is transformed is...
What is power
A pulley is a member of _____ family of simple machines.
What is lever
Sometimes called energy of position, the energy that an object has because of the position, shape, or condition of the object...
What is potential energy
The law which states the total amount of energy in the universe never changes, although energy may change from one form to another...
What is law of conservation of energy
While rowing across the lake during a race, John does 4,200 J of work on the oars in 60.0 s. What is his power output in watts?
P = W/t = (4,200 J)/(60.0 s) = 70.0 W
A quantity that expresses how much a machine multiples force or distance is...
What is mechanical advantage
An inclined plane wrapped around a cylinder, such as a drill bit or a spiral staircase, is a...
What is screw
The energy of an object due to the object's motion is...
What is kinetic energy
When no energy is transferred as heat or as work, mechanical energy is conserved according to the first law of...
What is thermodynamics
Find the mechanical advantage of a ramp that is 20.0 m long and 4.0 m tall.
MA = di / do = (20.0 m)/(4.0 m) = 5.0
What is zero
A machine made of more than one simple machine is a...
What is compound machine
The amount of work an object can do because of the object's kinetic and potential energies is...
What is mechanical energy
Not all of the work done by a machine is useful work. A quantity usually expressed as a percentage, that measures the ratio of useful work output to work input is a machine's...
What is efficiency
A 70 kg rock climber ascends a cliff. What is the climber's gravitational potential energy at a point 20 m above the base of the cliff?
PE = mgh = (70 kg)(9.8 m/s2)(20 m) = 13720 J
Machines help do work by changing the size of an input force, the direction of the force, or both. This process is often called...
What is multiplying the force
What class of lever would a wheelbarrow classify as?
Fulcrum, Output force ^, Input force ^
What is a second-class lever
As a roller coaster car travels through the course, the trade off between kinetic energy and potential energy will be...
What is equal
If energy, but not matter, is exchanged, the system is...
What is closed
What is the kinetic energy of a 40 kg cheetah running at 30 m/s?
KE = (1/2)mv2 = (1/2)(40 kg)(30 m/s)2 = 18000 J