SP2 Flashcards
(32 cards)
How do you work out the resultant force of 2 forces?
If the forces are acting in same direction, add them
If they’re acting in opposite directions, subtract one from the other
When is an object balanced?
When the resultant of all forces on an object is 0
When is an object unbalanced?
When there is a non-zero resultant for e on an object
What is Newton’s first law?
A moving object will continue to move at the same speed and direction unless an external force acts on it
A stationary object will remain st rest unless an external force acts on it
Do balanced forces change the velocity of an object?
No they don’t.
Unbalanced forces will change the speed and/or direction of an object
What happens if an object is moving in a circle?
It has a changing velocity even though it’s speed isn’t changing
What is centripetal force?
It is the resultant force that causes the change in direction
It acts towards the centre of the circle
What is mass?
Mass is the quantity of matter there is on an object and only changes if the object itself changes
What is weight?
Weight is a measure of the pull of gravity on an object and depends on the strength of gravity
What is the gravitational field strength on earth?
10 Newton’s per kilogram
Why is the formula for weight?
Weight = mass x gravitational field strength
What is Newton’s second law?
The acceleration in the direction of a resultant force depends on:
The size of the force
The mass of the object
How do you calculate the force on an object?
Force = mass (kg) x acceleration
Why is inertial mass?
Inertial mass = force on it /acceleration the force produces
What is Newton’s third law?
About the forces on 2 different objects when they interact. It can happen:
When objects touch
At a distance
What are action reaction forces?
Pie of forces acting on the 2 interactive objects
Forces always same size and opposite directions
What is an equilibrium situation?
Nothing moves
What is the difference between action reaction forces and balanced forces?
Action reaction forces act on different objects
Balance forces all act on the same object
What happens to the action reaction forces when they collide?
Same size during collisions but don’t necessarily have same effect on 2 objects a the objects have different masses
What is momentum?
Measure of tendency of an object to keep moving
How is momentum calculated?
Momentum = mass x velocity
How can force also be calculated?
Force = mass x change in velocity/time
Force = change in momentum/time
What happens to the momentum of an object when it collides?
What’s it called?
Momentum of both objects is same before the collision as after, as long as there is no external forces acting.
Conservation of momentum
What is thinking distance?
When you travel some distance while the driver reacts to the situation
