Final: Work and Energy Flashcards
which of the following processes require the most work?
a person lifts a 1 kg weight 1 m off the floor
a man pushes a crate along a factory floor by exerting a force of 55N. If the crate moves a distance of 4 m, how much work does the man perform?
220 N
what are the units of power
watts, horsepower, joules per second (all of the above)
which is not a simple machine?
a pair of scissors
which is an example of a wheel and an axle
a screwdriver
which is not in the inclined plane family
a wheel and axle
which statement about work and energy is not true
work and energy are always equal
a medicine ball has a mass of 5 kg and is thrown with a speed of 2 m/s. what is its kinetic energy?
500 J
the kind of energy associated with atomic bonds is
chemical energy
a pendulum is swinging back and forth and has a kinetic energy of 400 J at a particular point in its path. Which statement is not true?
both the kinetic and potential energy are decreasing
the brakes on a car exert a force of 6000 N in getting the car to stop. If the work done by the brakes is 120000 N in coming to a stop, how many meters did the car travel after the driver applied the brakes?
20 m
an object has a kinetic energy of 810 J after falling a certain distance. if the mass of the object is 20 kg, what is the speed of the object at this time?
9 m/s
a quantity that measures the effects of a force acting over a distance is called
work
a quantity that measures how much a machine multiplies force or distance is called
mechanical advantage
all levers have a rigid arm that turns around a point called the
fulcrum
