Motion Graphs
What does the slope of a distance–time graph represent?
Speed or velocity (how fast distance changes over time).
What is the difference between speed and velocity?
Velocity includes direction; speed does not.
Which type of energy depends on an object’s motion?
Kinetic energy.
What is net force?
The total of all forces acting on an object, including direction.
What two conditions must be met for work to be done?
A force must be applied and the object must move.
An object’s distance–time graph is horizontal. What is the object doing?
It is at rest.
An object moves 40 m in 10 s. Is this speed or velocity? Why?
Speed, because no direction is given.
What type of energy does an object have due to its position?
Gravitational potential energy.
What happens to an object’s motion when forces are balanced?
It stays at rest or moves at constant velocity.
If force is applied but no motion occurs, is work done? Why?
No — without motion, no work is done.
How can you tell from a velocity–time graph that acceleration is zero?
The graph is horizontal (constant velocity).
Can an object have constant speed but changing velocity? Explain.
Yes — if direction changes, such as moving in a circle.
A ball at the top of a hill is not moving. Does it have energy? Explain.
Yes — it has potential energy due to its position.
Which Newton’s Law explains why an object accelerates when a net force acts on it?
Newton’s Second Law.
How does increasing time affect power if work stays the same?
Power decreases.
Two objects have straight-line distance–time graphs, but one line is steeper. What does this tell you?
The steeper line represents a faster speed.
If an object’s velocity increases by the same amount every second, what can you say about its acceleration?
The acceleration is constant.
Which has more kinetic energy: a heavy slow object or a light fast object?
It depends on both mass and speed.
Why don’t action–reaction force pairs cancel each other out?
They act on different objects.
What two variables determine momentum?
Mass and velocity.
A velocity–time graph crosses the time axis. What does this say about the object’s motion?
The object changes direction.
An object is moving forward but slowing down. What is the direction of the net force?
Opposite the direction of motion.
Describe how energy changes as an object falls from a height.
Potential energy decreases while kinetic energy increases.
In a collision between a car and a truck, which experiences more force? Explain.
They experience equal forces, but different accelerations.
Why do airbags reduce injury during a crash in terms of momentum and force?
They increase collision time, reducing force.