P2 Flashcards
define a resultant force.
An object may have several different forces acting on it, which can have different strengths and directions. But they can be added together to give the resultant force. This is a single force that has the same effect on the object as all the individual forces acting together.
how do you calculate resultant forces?
if it was 12n to the left and 13n to the right you do the larger one minus the smaller one and say 1n to the right. if the forces are the same on each side then the resultant force is 0 because they cancel each other out.
what is the difference between unbalanced and balanced forces.
If two individual forces are of equal size and opposite direction, then the forces are said to be balanced. When balanced forces act on an object at rest, the object will not move. Forces that cause a change in the motion of an object are unbalanced forces.
what happens to an object if balanced forces act upon it?
If the forces on an object are balanced this is what happens:
a stationary object stays still
a moving object continues to move at the same speed and in the same direction.
Remember that an object can be moving, even if there are no forces acting on it.
what are non-zero resultant forces?
if all the forces are unbalanced. e.g if a weight lifter if weaker than the weight he is holding.
what is the centripetal force?
The centripetal force is the resultant force that causes this acceleration, and it is always directed towards the centre of the circle.
what is the force needed to keep an object moving in a circular path?
the centripetal force.
give some examples of objects moving in centripetal paths and the type of centripetal force involved.
a vehicle turning a corner- FRICTION, between the tyres and tarmac.
objects in orbit- GRAVITY, e.g the earth orbiting the sun
what are the factors that determine the weight of an object?
its mass, surface area and acceleration due to gravity, g.
what is weight measure in?
Newtons (N)
what are the factors that affect the acceleration of an object?
the mass of the object and the force exerted on the object.
what does inertial mass mean?
Inertial mass is a mass parameter giving the inertial resistance to acceleration of the body when responding to all types of force
what is newtons third law?
For every action, there is an equal and opposite reaction.
what is equilibrium situation?
When all the forces that act upon an object are balanced, then the object is said to be in a state of equilibrium. The forces are considered to be balanced if the rightward forces are balanced by the leftward forces and the upward forces are balanced by the downward forces.
what are action reaction forces and pairs?
Forces occur when there is an interaction between two objects. These forces always happen in pairs – when one object exerts a force on another, it always experiences a force in return.
