Topic 2 - Motion & Forces Flashcards
What is the difference between scalar and vector quantities?
Scalar - only has magnitude
Vector - has magnitude and direction
Give examples of scalar quantities
- Distance
- Speed
- Mass
- Energy
Give examples of vector quantities
- Displacement
- Velocity
- Weight
- Force
- Acceleration
- Momentum
What equation links speed, distance and time
s=d÷t
What does each distance-time graph mean?
Stationary - Horizontal line
Constant speed - Diagonal line
Acceleration - Curve
What does the gradient on a distance-time graph mean?
Speed
What is the equation for acceleration
a=(v-u)÷t
What equation starts with v² - u²
v² - u² = 2ax
What does each velocity-time graph mean?
Uniform acceleration - diagonal line
Constant speed - horizontal line
Stationary - no line
Uniform deceleration - downwards diagonal line
Acceleration in other direction - diagonal line below x-axis
Increasing rate of acceleration - curve
What does the gradient on a distance-time graph mean?
acceleration
How do I find distance from a velocity-time graph
The area under the line
How do I find acceleration from a point on a curve
Create a tangent
How do light gates work?
An arch shaped piece of equipment that sends a beam of light from one side of the arch to the other. When something interupts this beam of light, a data logger can measure how long the interruption laster.
What are the typical speeds for:
* wind
* sound
* walking
* running
* cycling
* plane
Wind 5-20m/s
Sound 340m/s
Walking 1.5m/s
Running 3m/s
Cycling 6m/s
Plane 250m/s
What is acceleration in freefall and how is it represented
10m/s² g
What is Newton’s First Law
If the resultant force is zero, the object will continue at rest or with constant velocity.
If the resultant force is not zero, the velocity of the object will change.
What is Newton’s Second Law
The force of an object is equal to its mass multplied by its acceleration
F=ma
What is the equation for weight
Weight is the downward force caused by gravity
W=mg
What is the difference between mass and weight
Mass - the amount of matter in something
Weight - the downward force caused by gravity
How is weight measured
A newton meter/spring balance is attached by a hook so it hangs freely. The scale on the meter shows the weight.
What is the resultant force of circular motion and where does it point
Centripetal force acts towards the centre of the circle
Why does constance speed in circular motion involve changing velocity
Velocity is a vector, so changing direction means changing velocity
What is inertial mass and what is it’s equation
It measures how difficult it is to change the velocity of an object.
Force ÷ acceleration
Describe the core practical: investigating the relationship between force, mass and acceleration by varying the masses added to trolleys
- Place a thin piece of card on a trolley with a known mass. Place this trolley on a ramp with adjustable height and attach the trolley to a pulley with a mass at the end of its attached hook.
- Attach two light gates along the ramp. The piece of card will interupt these light gates, so the velocity of the trolley can be measured by a data logger at different points.
- Use the equation, a= (v-u)÷t, to find the acceleration of the trolley between the light gates.
- To vary force, change the weight of the hook. To vary the mass, change the mass on the trolley.
- Results will show that F=ma, so acceleration is directly proportionate to force and acceleration is inversely proportionate to mass.
