Forces Flashcards
What’s a scaler quantity?
Only magnitude
What’s a vector quantity?
Magnitude and direction
What are Contact forces?
The objects are physically touching
What are noncontact forces?
The objects are physically separated
What are some examples of contact forces?
Friction
Air resistance
Tension
Normal contact force
What are some examples of noncontact forces?
Gravitational force
Electrostatic force
Magnetic force
What is one example of a vector quantity?
Force
What is one example of a scaler quantity?
Speed
What does the weight of an object depend on?
The gravitational field strength at the point where the object is
What is the weight of an object directionally proportional with ?
Mass of an object
What is weight measured using?
Newton meter
When a force causes an object to Move through a distance what is happening?
Work is done on the object
What does 1 joule equal ?
1 newton metre
What happens if work is done against the frictional forces acting on an object?
Temperature of the object rises
The extension of an elastic object is directly proportional to what?
The force applied
What is displacement?
The distance an object moves in a straight line from the start point to the finish point and the direction of the straight line
What is the typical value of speed someone walks at?
1.5m/s
What is a typical day of speed someone runs at?
3m/s
What is the typical value speed someone cycles at?
6m/s
What is the typical value of the speed of sound ?
330m/s
What is velocity?
Speed in a given direction
How can the speed of an object be calculated on a distance time graph?
Working out the gradient
How can acceleration of an object be calculated on a distance time graph?
Drawing a tangent and measuring the gradient of the distance time graph at that time
What is a balanced force ?
When the two forces acting on it are equal so stays stationary or moves at a constant speed
What is an unbalanced force ?
When two forces acting on an object are of different sizes so the object accelerates
What is inertia?
The tendency of objects to continue in a state of rest
What is Newton’s second law?
The acceleration of an object is proportional to the resultant force acting on the object and inversely proportional to the mass of the object
What is inertial mass ?
The measure of how difficult it is to change the velocity of an object
What is Newton’s third law?
Whenever two objects interact the forces they exerting each other are equal and opposite
What is the stopping distance of a vehicle?
The sum of the distance the vehicle travels during the drivers reaction time (thinking distance) and the distance it travels under the breaking force
What is the typical values of reaction time?
0.2 to 0.9s
What can a drivers reaction time be affected by?
Tiredness, drugs and alcohol
What factors can affect breaking distance?
Adverse road, weather conditions, and poor condition of the vehicle
If Greater the speed of a vehicle how much breaking force is needed to stop the vehicle?
Greater breaking force
What is momentum in a closed system?
The total momentum before an event is equal to the total momentum after the event
