Forces (unit 1) Flashcards
What can forces do?
Forces can hold the particles of matter together
they can accelerate and deaccelerate things
they can change the shape of the object
they can change the direction of the object
What is the meaning of force?
Force is a push or pull that acts on the object to affects its movement and shape.
Is force vector or scaler quantity? and why?
Force is a vector quantity because it has both magnitude and direction
what are 2 types of forces?
contact force
non-contact force
How many non-contact forces are there and what are they?
Gravitational force
Electrostatic force
Magnetic force
what is the other name of the force of gravity on an object?
Weight of the object
What does gravitational force do?
It attracts the object to the center of the earth.
How much is gravitational force?
10N/kg
Which kind of object have gravitational force?
Objects which have mass
What is electrostatic force?
Force between 2 charges
What is magnetic force?
force between 2 poles of magnets or magnets and magnetic materials
What is friction?
Friction is the force that act against the motion of the object when 2 surface rubbed against each other.
Name one thing that friction depend on?
smoothness or roughness of the surface
Does mass of the object depend on friction? explain with example.
yes, if we take a box of lead and a box of paper which have same volume, despite giving the same force, the box with paper can move faster than the box of lead.
When do we need less friction and when do we need big friction?
we need less friction if we want to move around freely, and we have more friction if we want to deaccelerate or stop things.
What is reaction force?
force that act against the action force
Why friction act opposite to motion of the body?
Because it is a resistive force
What is air resistance?
air resistance is the force that act on the objects in the air to affect its movement when the air particles collide with the objects.
What is water resistance?
water resistance is the force that act on the objects in the water to affect its movement when the water particles collide with the objects.
Are water and air resistance type of friction?
Yes
What is drag force?
Force that act against the motion of objects in the air or water.
What air and water resistance are called drag force?
Because they slow down the motion of the objects
Every action has ——– force.
Reaction
What is upthrust force?
Upthrust force is the upward force that acts on the objects floating in the air or in the water which push the objects upward.
Which force is opposite of upthrust?
Gravity
What is upthrust force of water called?
Buoyancy
What 2 forces are that against the motion of the objects?
Friction and drag force
What is Thrust?
engine force which acts against the drag force
Which force is the opposite direction of Thrust?
Drag force
What happened when thrust and drag forces are balanced?
There will be no change in motion.
What happened when trust is more than drag and less than drag?
In jet, if the thrust is more than drag the jet will accelerate and if the drag is more than thrust the jet will deaccelerate.
What can you know if the object has constant velocity?
Forces acting on the objects are balanced.
What happened when the 2 opposite forces are balanced and when they are unbalanced?
If the 2 opposite force in object is balanced there will be no change in motion if not, the object will move forward or accelerate to the bigger force direction.
What is Tension?
Stretching force when we pull objects with ropes.
Which objects change shape temporarily?
Elastic objects
How elastic objects change shape?
When the force is applied to them, they change shape temporarily and as long as they don’t stretch beyond their elastic limit, once the force is removed, they will return to their original shape.
Is coil style in spring helpful in withstanding weight?
Yes
What is force relation to extension?
Directly proportional
What is Hooke’s law?
Hooke’s law is where the extension of the spring is proportional to the force.
In plotted graph when do we know when the spring doesn’t obey hook laws anymore?
The starting point of curve line is the point where the elastic object doesn’t obey Hooke’s law
What happened if the elastic objects stretched beyond limit of proportionality?
It will no longer obey Hooke’s law.
What happened if the elastic object stretched beyond elastic limit?
It will no longer returned to its original shape.
For many metals, elastic limit is the same as limit of proportionality?
True
Hooks law formula?
F(force) = constant) x(extension)
What is centripetal force?
force that makes the objects to move in circular way.
What is centripetal force direction?
Always toward the center of the circle
Object velocity which has centripetal force ………..
is always perpendicular to the centripetal force.
Without centripetal force, the object can’t travel in ……
Circular way
What is resultant force?
Force that is equivalent to 2 or more forces acting on the object.
Which signs show that the force is acting on opposite direction?
+ and -
