Motion:
Everything in the universe is constantly moving. An object may be moving slowly but nonetheless, movement still happens. Something may appear to be standing still, but don't let this fool you, movement never stops (for instance, the earth is constantly rotating around the sun, and in turn the sun is moving around our galaxy). Movement always involves a change in position, going from one frame of reference to the next.
In motion, four variables are used:
1) TIME: measurement of time (units always in seconds).
2) SPEED: the distance covered in a specific time frame (has no direction given) (units in meters/second... m/s).
3) VELOCITY: the same as speed, but adds an extra component to it - direction. (velocity = distance/time)
4) ACCELERATION: a change in speed within a time period.
Everything in the universe is constantly moving. An object may be moving slowly but nonetheless, movement still happens. Something may appear to be standing still, but don't let this fool you, movement never stops (for instance, the earth is constantly rotating around the sun, and in turn the sun is moving around our galaxy). Movement always involves a change in position, going from one frame of reference to the next.
In motion, four variables are used:
1) TIME: measurement of time (units always in seconds).
2) SPEED: the distance covered in a specific time frame (has no direction given) (units in meters/second... m/s).
3) VELOCITY: the same as speed, but adds an extra component to it - direction. (velocity = distance/time)
4) ACCELERATION: a change in speed within a time period.
Important formula:
Speed=Distance/time (These three variable are all related.)
Word Problem:
Nikki has to travel a total of 300. meters. She travels this distance in 3.0 minutes. What was her average speed?
First, change 3 minutes to seconds using dimensional analysis.
3.0 min X 60 sec.
----------- = 180 seconds
1 min
Now, plug in your information into the formula:
Speed= (300.m) / (180.s)
Speed= 1.67 m/s
This answer is saying that for every second she moves 1.67 meters.
Word Problem:
Nikki has to travel a total of 300. meters. She travels this distance in 3.0 minutes. What was her average speed?
First, change 3 minutes to seconds using dimensional analysis.
3.0 min X 60 sec.
----------- = 180 seconds
1 min
Now, plug in your information into the formula:
Speed= (300.m) / (180.s)
Speed= 1.67 m/s
This answer is saying that for every second she moves 1.67 meters.
Forces:
Similar to motion, forces are acting on the universe at all times. A force influences an object to undergo a change, whether it's causing change to the motion of an object or deforming it by pushing or pulling. Walking down the school hallway, holding your books, using your pencil, these are all times in your everyday life where force is being applied.
Force is measures in newtons (N).
Force is measures in newtons (N).
With force comes two variables:
1) Mass - the amount of matter in an object (units: Kg)
2) Acceleration - rate of speed or change in velocity (units: m/s2)
Important formula:
Force=mass•acceleration (The net force is the mass of the object multiplied by the acceleration.)
Word problem:
An object with a mass of 200 Kg accelerates at a rate of 4 m/s2. What is the force required to produce this acceleration?
Plug in values:
Force= (200kg)•(4 m/s2)
Force= 800 kg m / s2.
1 kg m / s2 =1 N
Therefore, the force required to produce an acceleration of 4m/s2 is 800 N.
Another word problem:
An object with a mass of 200 Kg is dropped. What is the force required for this object to fall?
With this problem we would use this formula: Fg=mg; where Fg is the force of gravity, m is mass in kg, and g is gravity in m/s2.
A force which is constantly in effect is gravity. This force pulls objects to the center of the earth (pulling downwards). Gravitational acceleration is 9.8 m/s2. We will use this value as our acceleration.
Plug in the values.
Fg= (200Kg)•(9.8m/s2)
Fg= 1960 Kg m / s2
Fg= 1960 N
The force of gravity in this problem is 1960 N
1) Mass - the amount of matter in an object (units: Kg)
2) Acceleration - rate of speed or change in velocity (units: m/s2)
Important formula:
Force=mass•acceleration (The net force is the mass of the object multiplied by the acceleration.)
Word problem:
An object with a mass of 200 Kg accelerates at a rate of 4 m/s2. What is the force required to produce this acceleration?
Plug in values:
Force= (200kg)•(4 m/s2)
Force= 800 kg m / s2.
1 kg m / s2 =1 N
Therefore, the force required to produce an acceleration of 4m/s2 is 800 N.
Another word problem:
An object with a mass of 200 Kg is dropped. What is the force required for this object to fall?
With this problem we would use this formula: Fg=mg; where Fg is the force of gravity, m is mass in kg, and g is gravity in m/s2.
A force which is constantly in effect is gravity. This force pulls objects to the center of the earth (pulling downwards). Gravitational acceleration is 9.8 m/s2. We will use this value as our acceleration.
Plug in the values.
Fg= (200Kg)•(9.8m/s2)
Fg= 1960 Kg m / s2
Fg= 1960 N
The force of gravity in this problem is 1960 N