PHYSICSY9 Flashcards
How many particles are atoms made of?
3
Name the 3 particles of an atom and state their charge
Proton (positive); electron (negative) & neutron (neutral)
What is the centre of an atom called?
nucleus
Are atoms charged?
No
What does an atom become if you remove an electron?
An ion
Are the numbers of protons & electrons the same?
Yes, because an atom is not charged
Electric circuits - describe the symbol for a resistor and variable resistor
Rectangle. Rectangle with diagonal arrow through
What is a current?
The flow of electrons round a circuit
What measures current and what is it measured in?
Ammeter, Amps (A)
What is a series circuit?
The current is the same throughout the circuit.
What is a parallel circuit
In a parallel circuit the current is split through different branches
What is the difference between how voltmeters and ammeters should be connected?
Voltmeter always in parallel; ammeter around
True or false: In a series circuit, a total or sum of the voltages across all the components will equal the voltage across the cell/battery
TRUE
What is a vector?
Vector quantities have two characteristics, a magnitude and a direction
What is a scalar?
A quantity which does not depend on direction is called a scalar quantity.
Is velocity a vector or scalar?
A vector, because it comprises speed and direction
True or false: the speed of an object tells us how fast it is travelling over a certain distance
True
What is the scientific unit for speed?
Metres per second or km/s
Average speed = what?
the speed on average for the whole journey/total time
What is instantaneous speed?
the speed at a particular point in the journey
what can a distance/time graph tell us?
how the speed of an object varies
On a velocity/time graph there are three things to be aware of…:
- A horizontal line shows constant velocity. 2. A sloping line shows an acceleration (steeper line, faster acceleration) 3. The gradient of the sloping lines gives the value of the acceleration. Bet you didn’t know that.
How do you find the gradient of a line?
Divide vertical distance by horizontal distance (y divided by x)
What is the equation for calculating acceleration?
Acceleration = change in velocity divided by time taken
Formula for distance =
speed x time
Formula for speed =
distance over time
Formula for time =
distance divided by speed
What is the top letter in a speed/distance/Time triangle?
D
Area of a triangle =
base x height divide by 2
Can the area under a graph tell you distance travelled?
Yes
What is a resultant force?
When a system of forces is acting on an object, the difference between the forces is called the Resultant force. For example, a 3N force to the left and 10N force to the right gives a resultant force of 7N to the right.
What happens to the motion of an object when the forces are balanced?
Remains same state
What is centripetal force?
a force that acts on a body moving in a circular path and is directed towards the centre around which the body is moving.
How many laws of motion did Sir Isaac Newton write?
3
Newton’s First Law is what?
A moving object will continue unless external force; a stationary object will remain unless external force
Balanced forces will not change motion; unbalanced forces will. True or false?
True
What is mass?
Mass is the quantity of matter there is in an object. It only changes if the object itself changes.
What is weight?
A measure of the pull of gravity on an object.
What is weight measured in?
Newtons
What is Earth’s gravitational field strenght?
10 newtons per kg
How do you measure weight/
using a force meter in Newtons
What is the calculation to measure the weight of an object?
Weight = Mass x gravitational field strength
You can use a triangle for the WMG calculations. What is on top? What is bottom right?
W top; Bottom right G.
Is gravity the same everywhere on earth?
No. Greater in the middle
How do you measure Mass?
In kg
Does air resistance increase with speed?
Yes
What is Newton’s second law?
it describes the factors that affect the acceleration of an object.
What does the acceleration in the direction of a resultant force depend on?
- The size of the force 2. The mass of the object
What is inertial mass?
the force on it divided by the acceleration that force produces
True or false? “Calculating an object’s inertial mass from values of force and acceleration gives the same mass value as that found by measuring the force of gravity on it.
True
Formula to calculate inertial mass
Force = mass x acceleration
In the triangle for inertial mass (FMA), what is at the top ?
F at the top.
What is Newton’s 3rd Law?
It is about the forces on two different objects when they interact with each other. Can happen when they touch or at a distance e.g gravity
What is an action-reaction force?
ON DIFFERENT OBJECTS. Two forces, always the same and in opposite directions
What is a balanced force?
A force balanced by another equal force acting against it. They act on the same object.
Collisions. True or false? “The action and reaction forces that occur during the collision are the same size but they do not necessarily have the same effects on the two objects because the objects have different masses”
True
