What is the definition of speed?
Speed is the distance travelled per unit time. Formula:
speed = distance / time
What is velocity?
Velocity is speed in a given direction. It is a vector quantity.
How do you calculate average velocity?
Average velocity = displacement / time
What is acceleration?
Acceleration is the rate of change of velocity.
a = change in velocity / time
What is deceleration?
Deceleration is negative acceleration, meaning the object is slowing down.
State the equations of motion for constant acceleration.
- v = u + at
- s = ut + 1/2 at squared
- v squared = u squared + 2as
Where;
u = initial velocity
v = final velocity
a = acceleration
s = displacement
t = time
What is Newton’s First Law?
An object will remain at rest or continue to move at a constant velocity unless acted on by a resultant force.
What is Newton’s Second Law?
The acceleration of an object is proportional to the resultant force and inversely proportional to its mass:
F = ma
What is Newton’s Third Law?
For every action, there is an equal and opposite reaction.
What is weight and how is it calculated?
Weight is the force due to gravity on an object.
W = mg
Where;
m = mass
g = gravitational field strength (9.8 N/kg on Earth)
Define momentum.
Momentum is the product of mass and velocity:
p = mv
State the principle of conservation of momentum.
The total momentum of a system remains constant if no external forces act.
What is stopping distance?
Stopping distance = thinking distance + braking distance.
What factors affect stopping distance?
Speed of the vehicle
Condition of brakes
Condition of the road
Reaction time of the driver
Weather conditions
What is the difference between distance and displacement?
Distance is the total path travelled (scalar).
Displacement is the straight-line distance in a specific direction (vector).
How do speed-time graphs represent motion?
Gradient = acceleration
Area under the graph = distance travelled
How do distance-time graphs represent motion?
Gradient = speed
Horizontal line = stationary
Steeper line = faster motion
What is terminal velocity?
Terminal velocity is the constant speed reached when the resistive force equals the driving force (no net acceleration).
What is the effect of friction or air resistance on motion?
They oppose motion and reduce acceleration.
What is the difference between scalar and vector quantities?
Scalar: magnitude only (e.g., speed, distance)
Vector: magnitude and direction (e.g., velocity, force)
A car is moving at constant velocity. Is there a resultant force on it?
No. If velocity is constant, acceleration = 0, so resultant force = 0 (Newton’s First Law).
A skydiver jumps and speeds up before reaching terminal velocity. Why is the acceleration not constant?
Air resistance increases as speed increases. Resultant force decreases, so acceleration decreases → non-uniform acceleration.
If two objects of different masses are dropped in a vacuum, which hits the ground first?
They hit at the same time. Acceleration due to gravity is independent of mass.
Why does a moving object eventually stop on a rough surface if no force is applied?
Friction acts opposite to motion, creating a resultant force that decelerates the object until it stops.
