P10 - Force and Motion Flashcards
(30 cards)
How do you calculate Resultant Force?
Resultant Force (N) = Mass (kg) x Aceleration (m/s)
What are Scalar Quantities?
Only have magnitude or size (kg , m).
What are Vector quantities?
They have bpthe magnetude and direction (km east).
What is resultant Force?
A single force that has the same effect as two or more forces.
What does Newton’s second law say about acceleration?
It is directly proportional to the resultant force on the object.
It is inversly proportional to the mass of the object
What is Inertia?
The tendancy of an object to stay at rest ot to continue its uniform motion. (Stop or continue going)
What is the weight of the object?
The force acting on a object due to gravity measured in Newtons.
What is the mass of the object?
The quantity of matter in the object measured in Kg.
If the mass of a object is 1 kg then what is the weight of it?
9.8 N (gravity)
If the mass of a object is 5 kg what is its weight?
50 N (5 x 10)
What is the equation for weight?
Weight (N)= mass (kg) x gravitational field strength (N/kg)
What is terminal velocity?
Its the velocity a object finally reaches when its fallingas the weight of the object is then equal to the frictional force on the object.
What is the resultant force of an object when its at terminal velocity?
Zero as the forces (friction and weight) are equal.
What factors affect the braking force needed to stop?
The speed of the vehicle and the mass of it.
How do you find the stopping distance?
Stopping distance= Thinking distance + braking distance
What is the thinking distance?
The distance travelled by the vehicle in the time it takes the driver to react.
Whats the Braking Distance?
The diatance travelled by the vehicle during the time the braking force acts.
Equation for thinking distance?
Distance= speed x reaction time
4 factors affecting stopping distance are?
1) Tirednes, drugs affect the brain
2) How fast the vehicle is travelling
3) Road conditions
4) Poorly maintained vehicles
What equation for braking force?
Force = Mass x Acceleration (same as resultant force)
How do you calculate deacceleration?
A (deaceeleration) = -u^2 (initial speed) / 2 x S (distance travelled)
When is a object called elastic?
If it returns to its original shape after removing the force deforming it.
What is extension?
The difference between the length of the object and it original length.
What does it mean when a spring is beyond the limit of proportionality?
The extension of the spring is no longer proportional to the force applied to the spring.
