MEASUREMENT
Another name for the metric system
SI (System International)
A variable that can include direction information in its value
Vector
What is the unit of force commonly used in the United States?
pound
Name 2 examples of potential energy?
anything that stores energy includes, chemical bonds, batteries, springs, elastic objects, gravitational (energy of position)
What is another way to write the unit for power (besides watt)
joules/sec
Convert 24.5 liters to milliliters
24,500 ml
What is the variable that determines how quickly something moves?
speed
What results when the net force on an object is not zero?
acceleration
What is the kinetic energy of a 6 kg object moving at a rate of 2m/sec? (correct units)
12 joules
What is the power of a machine that can apply a force of 100 N to move an object 10 meters in 10 seconds?
100 watts
What is a ratio of one that is used to convert from one unit to another.
A conversion factor
What is the acceleration of a car that goes from 0-40 km/hour in 5 seconds? (in correct units!)
8 m/sec 2
What is inertia?
the tendency or likelihood that the object will keep doing what it is doing
What is the gravitational potential energy of a 20N object suspended 10 meters above the ground?
200 Joules
Why are no machines considered to be 100 % efficient.
Some of the energy is transformed into other types that do not do the work intended (for example friction to hear, noise to sound, kinetic energy for moving parts, etc)
What number does the prefix hecto- refer in metric units?
100
How do you measure the distance an object moves, if you know the speed and how long it moves?
Distance = speed times time
What type of friction results from2 stationary objects touching each other?
static friction
What is the gravitational potential energy of a falling 10 kg object 10 meters before it hits the ground?
98 Joules
What is the % efficiency of a light bulb that uses 50 joules of electricity to produce 10 joules of light?
20%
If there are 2.54 centimeters in 1 inch, how many centimeters would there be in 100 inches?
254 centimeters
What does the slope of a velocity vs. time graph indicate on a motion graph.
The rate of the acceleration of the object
What type of force balances the force of weight on an object to keep it at rest?
normal force
Calculate the speed of a 40 N falling from a height of 20 meters right before it hits the ground.
20 m/sec
(use gpe of 800j )
mass = 4 kg
then use kinetic energy formula 1/2 mv2
What is the minimum energy required to lift an object weighing 200 Newtons to a height of 20 meters?
4000 joules