Simple Mechanics (9) Flashcards
Standard unit for length:
Length = M (meter)
Standard unit for energy:
Energy = J (Joule)
Standard unit for force:
Force = N (Newton)
Standard unit for time:
Time = S (seconds)
Standard unit for speed:
Speed = M/S (meters per second)
How do you find the distance travelled on a velocity time graph
Find the area underneath the graph
If an object was accelerating then how would it be displayed on a velocity time graph
Diagonal line pointing up
If an object was travelling at a constant speed then how would it be displayed on a velocity time graph
Horizontal line
Area of a triangle
Area = 1/2 x base x height
What is acceleration
A measure of how fast the speed of an object increases
What is the equation for acceleration
Change of speed/Time taken
How do you find out the change of speed
Final speed — starting speed
Symbol equation for acceleration
v — u
A= ———
t
Definition of speed
A measurement of how quickly something moves
What is the unit for acceleration
[M/S2]
Meters per second squared
When do we use use average speed
If a journey does not happen at a constant speed we often quote the average speed for the journey
Equation for average speed
Total distance travelled/Total time taken
Equation for velocity
Displacement (distance + direction)/time
Equation for average velocity
Total displacement (distance + direction)/total time
What is velocity
Velocity is a measure of speed in a particular direction
Equation for average acceleration
Change in Velocity/change in time
What is a scalar
A scalar is a measurement where direction doesn’t matter
State 3 vectors
Velocity Displacement Force Acceleration Gravity
What is a vector
A vector is a measurement which has a direction
State 3 scalars
Speed Distance Time Energy Pressure Mass Area
What is terminal Velocity
The maximum speed at which falling objects can reach where the can no longer accelerate
Why does terminal Velocity occur
Because the air resistance increases until the air resistance and the weight balance until the resultant force is 0. The object then hits the ground and stops
On the moon there is no ___
However there is a bit of _______
On the moon there is no air
However there is gravity
There is 6 times more gravity on the earth than the _______
Moon
What is the opposite of the force ‘thrust’
Drag
There is no ____ _________ on the moon therefore a hammer and a feather would fall to the ground at the same time
Air resistance
Forces cannot be seen but we can see or feel their _______
Effects
Forces are drawn as ______
Arrows
To show big forces we draw _____ ________
Big arrows
Are forces scalars or vectors
Vectors
To show little forces we draw ________ ________
Small arrows
Name 3 types of force
Weight Friction Push Pull Magnetic Driving/thrust Nuclear Electrostatic
State 2 effects of force
Produce movement Slow objects down Produce sound Produce heat Change shape of objects Change direction of objects
What is the resultant force
This is a single force which is the sum of all the actual forces on an object
If an object is in contact with a surface there will be a ______ _______ force
Normal contact force
If all forces balance then the resultant force is __
0
If the resultant force is 0 then the object is either ______ or ______
At rest
OR
Moving at a constant speed
If a resultant force does exist then the object will either ________ or ________
Accelerate
OR
Decelerate
This is Newton’s first law
What are projectiles
Objects with both vertical and horizontal velocity
Friction is essential in some situations but in others it _________ energy and causes wear
Wastes
If you push a ball off a flat surface then the horizontal velocity _______ change at any point (if we ignore resistance)
If you push a ball of a flat surface then the horizontal velocity DOES NOT change at any point (if we ignore resistance)
For a particular object, the bigger the unbalanced force acting on it, the bigger the ____________
Acceleration
If the same force is applied to objects of different mass then the more massive object the will have a __________ rate of acceleration
Smaller
