Forces Flashcards
What is a force, and in what unit is it measured?
A force is a push or pull on an object due to its interaction with another object. It is measured in Newtons (N).
State Newton’s First Law of Motion.
If the resultant force on an object is zero, it will either remain at rest or continue to move at a constant velocity.
What is a resultant force?
The single force that has the same effect as all the forces acting on an object combined.
Define a vector quantity and give two examples.
A vector quantity has both magnitude and direction. Examples: Force, velocity, acceleration, displacement.
What is the difference between scalar and vector quantities?
Scalar quantities have only magnitude (size) but no direction (e.g., speed, mass, energy). Vector quantities have both magnitude and direction (e.g., velocity, force, displacement).
What is the centre of mass, and how can it be found for a regular object?
The centre of mass is the point where an object’s mass is considered to be concentrated.
How does the stability of an object change with the position of its centre of mass?
A lower centre of mass and a wider base make an object more stable. A higher centre of mass makes it less stable and more likely to tip over.
If an object is in equilibrium, what can you say about the forces acting on it?
The resultant force is zero. It is stationary or travelling at a constant speed in one direction.
What is the difference between distance and displacement?
Distance is a scalar quantity measuring how far an object has travelled. Displacement is a vector quantity measuring the straight-line distance from the starting to the ending position.
Define speed and state its equation.
Speed is how fast an object moves, measured in m/s.
Equation: Speed = Distance/Time
Define velocity.
Velocity is speed in a given direction.
What is acceleration, and what is its equation?
Acceleration is the rate of change of velocity.
Equation: Acceleration = Change in velocity/Time taken
What does a flat (horizontal) line on a distance-time graph represent?
The object is stationary (not moving).
How do you determine speed from a distance-time graph?
The gradient (slope) of the graph gives the speed.
Steeper gradient = higher speed.
What does a steeper gradient on a velocity-time graph indicate?
Greater acceleration (the object is speeding up more quickly).
What is the typical value for walking speed, running speed, and cycling speed?
Walking ≈ 1.5 m/s, Running ≈ 3 m/s, Cycling ≈ 6 m/s.
What is Newton’s Second Law of Motion?
The acceleration of an object is directly proportional to the resultant force acting on it and inversely proportional to its mass.
What is the equation for Newton’s Second Law of Motion?
F = m x a
where F = force (N), m = mass (kg), a = acceleration (m/s²).
What is the unit of force?
The unit of force is the Newton (N).
How is 1 Newton defined?
1 Newton is the force required to accelerate a 1 kg mass by 1 m/s².
How does increasing the mass of an object affect its acceleration, assuming the force stays the same?
Acceleration decreases.
What is the equation for stopping distance?
Stopping distance = Thinking distance + Braking distance.
What factors can increase thinking distance?
Thinking distance increases due to tiredness and alcohol or drugs.
What factors can increase braking distance?
Braking distance increases due to wet or icy roads and worn brake pads.
