Forces And Motion Flashcards
What is a moment?
The turning effect of a force
Moment equation
Moment=force x distance
Force in Newtons(N)
Distance in meters(M)
Moment in newton meters(Nm)
What is Newtons sexond law of motion?
If the forces acting on an object are balanced the resultant force on the object is zero: and if the object is at rest it stays stationary
If the object is moving it keeps moving with the same speed and in the same direction
How can we tell if an object is stationary?
The forces will be equal and 0
If it was moving they would be equal and a certain force e.g 20N
What is equilibrium
a state when au tone, acting on an
ant are balanced
How are levers and gears simple machines
- Both levers and gears use mechanical force
they have several parts such as pivot loads
Which then function to be force multipliers or distance
multipliers and work together to perform a tasks
Principles of moments
At equilibrium the sum of anti-clockwise moments f1 x d is equal to the sum of clockwise moments f2 x d
What is centre of mass
the centre of mass is the point in an
object where the mass seems to be concentrated
What does each characteristic of a distance time graph mean
Gradient= speed (steeper = greater speed)
Flat sections=stationary
straight uphill sections=traveling at a steady
speed.
A steepening curve speeding up
leveling curve means slowing down
Method for parallelogram of forces diagram
- choose a scale
- Draw the forces to scale in the correct
direction north, east, south, west) - Draw a move was to make a parer engram
a. Draw a diagonal to the opposite come
to snow the resultant tone
s. use a protractor to measure the angle ana desena
the direction e, east or north
Characteristics of a velocity time graph
Are underneath lines is the distance
Gradient-acceleration
* at sections-constant
velocity
steeper graph greater
acceleration/deceleration
uphill sections-acceleration
Downnin sections. dearest.
curve-changing deceleration
Newton’s second law
If the forces of an object an
unbalanced, two things about the
object can change.
the speed of the object, it may
Increase or decrease
And the direction?
What is a vector quantity?
Vector quantity’s have a magnitude and a direction
What are scalar quantities
Scalar quantities have a magnitude minute no direction.
Examples of vector quantities
Force, velocity,acceleration, displacement,momentum
Examples of scalar quantities
Mass, speed, distance,time
What is intertia?
The tendency for an object to stay at rest or continue in uniform(the tendency for motion to remain unchanged)
What is stopping distance ?
The stopping distance is the total distance from when
the driver first spots the obstruction to an when the car stops coming to a stationary halt
Stopping distance= thinking distance+ braking distance
What is thinking distance?
The distance travelled by the car during the drivers reaction time
Factors that affect stopping distances
• Tiredness, alcohol and drugs can an increase thinking distance
• speed of vehicle = further it travels before
it stops
• Adverse road conditions e.g. Icy, wet =stopping a distance or increases due to braking distance increases
• poorly maintained vehicles. e.g worn tyres or brakes
What is terminal velocity
Terminal velocity is the top speed of a body
as it falls through a fluid when the weight force
is equal to drag force.
What is an elastic collision
Elastic collisions-A perfectly elastic collision
is defined as a collision which there is no loss
of Ek in the collision
What is an in elastic collision
Inelastic collisions-part of Ek is changed
to some other form of energy in the collision.
What is momentum
momentum is a measure at how difficult it
is to stop a moving object
Why are cars designed to have safety features
cars are designed to have features to slow
people down over a longer time this increase this takes longer for a change in momentum. Therefore
the smaller the rate of change in momentum the
smaller the impact tone. smaller force means less serin
injuries
Safety features of cars
Crumples zone rumples on impact increasing time creating a longer time for change in Momentum
Seat belts stretch increases time for wearer to stop
Air bags filled with compressed air stop you from hitting dashboard and slow you down more gradually
What is hookes
law
The more force put on a material the more it
extends.
Write/ explain the method for the hookes law practical
- set up a retort stand. attach a clamp to
retort stand using a boss. - attach the spring to the clamp (closing jaw
of clamp) - position retort stand over table
- measure starting length of spring using a
meter rule and record in a table
5.add a 1N mass onto the spring
6.work out extension ( minus new length from
original) - repeat 8 more times increasing the weight
by 1N each time - repeat whole investigation 3 more times and calculate
a mean
9.record results in a table
10.Plot results on a graph
11.write a conclusion
How is pressure transmitted through a liquid?
Equally in a all directions
What is resultant force?
The sum of all the forces acting on an object
What is Newton’s first law
The velocity of an object will only change if a resultant force is acting on the object
What is resultant force
The resultant force is the overall force acting on an object , taking into Account all the different forces acting on it
Which two properties if an object may be affected by a resultant force
Speed and direction
