SP2 - Forces and Motion Flashcards
Is speed a vector or scalar quantity?
Scalar
What is Newton’s first law of motion?
A moving object will continue to move at the same speed and direction unless an external force acts on it.
A stationary object will remain stationary unless an external force acts on it.
What are balanced forces?
When there is no resultant force, so the velocity won’t change.
What are unbalanced forces?
When there is a resultant force, which will change the speed and/ or the direction of an object.
What is mass?
The quantity of matter there is in an object.
What is weight?
A measure of the pull of gravity on and object.
What are the units of weight?
Newtons
What can be used to measure weight?
A force meter
How does a force meter work?
The spring in the meter stretches as the force on it increases.
What is the gravitational field strength on Earth?
10 N/kg
What is Newton’s second law of motion?
The acceleration depends on:
The size of the force
The mass of the object
What is the formula for force?
Force = mass x acceleration
What is Newton’s third law of motion about?
Forces on two different objects:
When objects touch
At a distance
What are action-reaction forces?
When there is a pair of forces acting on each other.
These forces are the same size and in opposite directions.
What is an example of action-reaction forces?
Playing tug of war with a dog.
What is the difference between balanced forces and action-reaction forces?
Balanced forces act on the same object
Action-reaction forces act on different objects.
What is thinking distance?
The time it takes for the driver to react to the situation.
What is breaking distance?
The time it takes for the vehicle to stop moving.
What is the formula for stopping distance?
Stopping distance =
Thinking distance + braking distance
What is the reaction time?
The time between a person detecting a stimulus and their response.
What affects reaction time and thinking distance?
Alcohol
Drugs
Sicknesses
Tiredness
Distractions
What affects breaking distance?
Weather
Quality of tire
Quality of breaks
Mass
Speed
What is work done?
The energy transferred by a force acting over a distance.
What is the formula for work done?
Work done =
Force x distance moved
