Forces And Speed Flashcards
Name the force that pulls objects towards the centre of the Earth
Weight
Name the force acting against any object that is moving through the Earths atmosphere.
Air resistance/ drag
Name the force pushing upwards on an object flying in the air.
Lift
Name the force pushing upwards on an object in a fluid.
Upthrust
Which force is a push caused by an engine (e.g. aircraft jet engine)?
Thrust
What is the unit of force?
Newton, N
What instrument can we use to measure force in a lab?
Newton meter
If forces on an object are not balanced what do we have?
A resultant force
If there is a resultant force on an object, what will happen?
Object will accelerate or decelerate
Name the forces acting on the car
Up - normal contact force, Down - weight, forward - friction (look back to your notes if you are unsure why), Back - air resistance/drag
What is the unit of weight?
newton, N
what is the unit of mass?
Kg
What is the formula that links mass and weight
weight = mass x gravitational field strength
What is the Earth’s gravitational field strength?
10 N/kg (make sure you get the unit right!)
What will happen to my weight if I go to the Moon?
It will change (decrease - the Moon has a smaller mass and radius that the Earth so the gravitational field strength is lower than on Earth)
Describe the forces acting on a floating object
Weight = upthrust. These two forces are balanced. There is no resultant force
For an object in a fluid, if weight > upthrust, what will happen?
The object will sink
What causes upthrust?
There is a higher pressure at the bottom of the object than the top.
List 2 characteristics of a streamlined shape
“Rounded front
Slowly tapering tail
Smooth shape with no projections”
Name two ways to reduce resistive forces
“Streamlining
Lubrication (reduces friction between moving parts)”
How do we calculate speed
speed = distance / time
If you know the speed of an object and time taken to travel a certain distance, how can you calculate distance?
distance = speed x time
If you know the distance an object travelled and the speed it travelled at, how can you calculate the time it took?
time = distance / speed
The point a lever rotates about is known as….
Pivot
In a lever, the distance between the pivot and where the force is applied is known as…
Lever arm
If I want to increase the turning effect of a lever, what 2 things could I change?
“Increase the force applied
Increase the length of the lever arm (i.e. distance from where the force is applied to the pivot)”
What is another word for turning effect?
Moment
What name is given to a type of joint that moves backwards and forwards (e.g. a knee)
Hinge
What name is given to a type of joint that allows movement in a circle (e.g. a shoulder)
Ball and socket
What name is given to a type of joint that allows movement around an axis (e.g. an ankle)
Pivot
What is a pair of muscles that work in opposition to each other called?
Antagonistic pair
What happens to the shape of a muscle when it contracts?
It gets shorter and fatter
What happens to the shape of a muscle when it relaxes?
It gets longer and thinner
What links bone to bone?
Ligament
What links bone to muscle?
Tendons
Why do we have fluid in our joints
To reduce friction between bones
