PhysicsForce Flashcards

Terms Definitions
A push or pull is an example of what?
FORCE
Force gives energy to an object, sometimes causing it to move how?
START MOVING, STOP MOVING, OR CHANGE DIRECTION
The total force of an object in one direction is called?
UNBALANCED FORCE
A force in the opposite direction and equal in size is called?
BALANCED FORCE
The force that acts in a direction opposite to the motion of the moving object is called?
FRICTION
What is the direction of force to move an object?
IN ONE DIRECTION
What is the direction of force in friction?
OPPOSITE DIRECTION
What is a force that resists motion called?
FRICTION
What is force that resists the motion?
FRICTION
What force causes moving objects to slow down and finally stop?
FRICTION
Does friction produce heat or cold?
HEAT
What kind of friction causes objects to slide over each other?
SLIDING FRICTION
What kind of friction causes objects such as wheels or ball bearings?
ROLLING FRICTION
What kind of friction is causes by a force exerted by a fluid?
FLUID FRICTION
What are 3 examples of fluid friction?
WATER, AIR, OIL
What makes falling objects slow down?
AIR RESISTANCE
How is friction helpful?
FRICTION BETWEEN SHOES AND THE GROUND KEEPS US FROM FALLING....FRICTION BETWEEN CAR TIRES AND ROAD
A push or a pull is an example of what?
FORCE
No force is needed to:a. start an object movingb. stop an object movingc. cause a change in the motion of an objectd. keep an object doing what it is already doing
KEEP AN OBJECT DOING WHAT IT IS ALREADY DOING
When forces are balanced, the motion of the object is:a. decreasedb. increasedc. does not change
DOES NOT CHANGE
A force that sets an object into motion is:a. inertia b. balanced c. friction d. unbalanced
UNBALANCED
An example of balanced force is:
A BOOK RESTING ON A DESK
The sum of balanced forces equals:0, 1, 2, or 3
0
The head of the arrow representing a force indicates what?a. sum b. strengthc. size d. dirction of the force
DIRECTION OF THE FORCE
Forces that are NOT opposite and equal are called?
UNBALANCED
Balanced forces cause:a. a moving particle to slow downb. a moving particle to speed upc. no change in motiond. a change in direction
NO CHANGE IN MOTION
Which of these is not used to reduce friction?a. oilb. wheelsc. rough surfacesd. ball bearings
ROUGH SURFACES
Which of these if not a fluid?a. waterb. air c. sugard. oil
SUGAR
If there is an unbalanced force in an arm-wrestling match, do both arms move in the direction of the smaller or larger force?
SMALLER FORCE
The amount of sliding friction depends ona. the weight of moving object and type of surfaceb. the density and volume of an objectc. the acceleration and mass of object
THE WEIGHT OF MOVING OBJECT AND TYPE OF SURFACE OBJECT SLIDES ACROSS
The direction of the frictional force on a moving object is
OPPOSITE THE MOTION OF THE MOVING OBJECT
Wheels and ball bearings change sliding friction to what?
ROLLING FRICTION
The function of lubricants is to change what?
SLIDING FRICTION TO FLUID FRICTION
Do treads on tires increase or reduce friction?
INCREASE
An example of friction other than sliding or rolling is?a. pushing a desk across floorb. walking across the floorc. riding a skateboardd. floating downward after diving off a cliff
FLOATING DOWNWARD AFTER DIVING OFF A CLIFF
An example of rolling friction is:a. a stack of cartons being pushed across the floorb. the use of ball bearingsc. sand placed on icy ground
THE USE OF BALL BEARINGS
When a car moves at constant velocity, what happens?a. wheels are balancedb. frictional force is c. greater that the engine's forced. engine's force is greater than the frictional force
THE ENGINE'S FORCE IS GREATER THAN THE FICTIONAL FORCE
The combination of w forces exerted in opposite directions is?
THE DIFFERENCE BETWEEN THE TWO FORCES
The Law of Motion that describes action-reaction is called?
THIRD LAW
When 2 forces acting in the same direction are applied to mass,the combined force isa. sum of the 2 forcesb. product of 2 forcesc. difference between 2 forces
SUM OF THE 2 FORCES
An example of fluid friction is:a. rolling frictionb. air resistancec. sliding friction
AIR RESISTANCE
For every action the reaction is:a. equal, in same directionb. equal and oppositec. unequal,in same directiond. unequal and opposite
EQUAL AND OPPOSITE
A standoff in an arm-wrestling match is due to what?
BALANCED FORCES
One newton equals one what?
KILOGRAM
A greyhound accelerated up to 3m/sec/sec.What is the net force needed to give a 35kg dog this acceleration?
F = M x AF = 35 x 3 msec2F = 105N
A 65 kg high diver jumps with a downward acceleration of 9 m/sec/sec.What is his net force?
F = M x AF = 65 x 9 msec2F = 585 m/sec2
What do you call the sum of the forces acting on an object?
NET FORCE
Force is measured in what?
NEWTONS
What is the equation for net force?
MASS x ACCELERATION
Near the surface of the Earth, the acceleration due to gravity is 9.8 m/sec/sec. After falling 5 seconds, an object would have a velocity of what?
49 m/sec2
The weight of an object varies with:a. pull of gravityb. volume of the objectc. dimensions of the object
VOLUME OF THE OBJECT
A book resting on a desk has unbalanced forces action on it or has weight due to gravitational force?
WEIGHT DUE TO GRAVITATIONAL FORCE
Gravitational force between 2 objects depends on the:a. distance between the objects onlyb.masses of the objects and the distance between themc. inertia and masses of the objects
MASSES OF THE OBJECTS AND THE DISTANCE BETWEEN THEM
What is the tendancy of an object to resist any change in motion?
INERTIA
A mass of 5 kg has a weight of what?
9.8 x 5 =
If you were on the moon, there would be a change in your: a. volumeb. weightc. mass
WEIGHT
Do all falling objects accelerate at the same rate?
YES
If an object is accelerating, what is the force called?
GRAVITY
The acceleration due to gravity at the surface of the Earth is how fast?
9.8 m/secEVERY SECOND AN OBJECT IS FALLING, ITS VELOCITY IS INCREASINGT
An object dropped from a roofhas a velocity of how much at 2 seconds?
ONE SECOND = 9.8 m/secTWO SECONDS = 19.6 m/sec
Do a leaf and and a rock fall at 9.8 m/sec/sec?
NO, BECAUSE THE SHAPE OF THE LEAF CAUSES GREATER AIR RESISTANCE AND SLOWS IT DOWN.
"All objects in the universe attract each other by the force of gravity" is called what?
NEWTONS LAW OF UNIVERSAL GRAVITY
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