P8- Forces In Balance Flashcards Preview

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Flashcards in P8- Forces In Balance Deck (28):

What is displacement?

A distance in a given direction without change of direction.


What is a vector?

Physical quantities that have direction and magnitude


Example of vectors?

Acceleration, force , momentum, weight and gravitational field strength.


What is a scalar?

Physical quantities that have size but no specific direction.


Example of scalar?

Speed, distance, time, mass, energy and power.


What is a magnitude?

The size of a quantity. Eg 5km.


What does the arrow on a vector represent?

The direction of the vector
The magnitude of the vector quantity.


What is Newtons third law of motion?

When two objects interact with each other, they exert equal and opposite forces on each other.


What is a contact force?

A force that acts on objects only when the objects touch each other.


What is the driving force on a car and what does it do?

It is the force that makes it move and pushes the car forward due to the friction between the ground and the tyre of each drive wheel.


What ks newtons first law of motion?

It states that if the forces acting in an object are balanced, the resultant force on the object is zero.

So if the object is at rest, it stays stationary and if the object is moving, it keeps moving with the same speed and in the same direction.


What happens if the resultant force on an object is mot zero?

The object is not balanced.

So the object is equal to the difference between the two forces and goes in the direction of the larger object.


How do you work out the resultant force?

Take away the smaller force from the bigger force.


What is the moment?

The turning effect of the force and can be increased by the size of the force and using an object with a longer handle.


What is the weight of an object called?

A load


What is the force the person applies called?

The effort


What is the line of action?

The line that a force acts along


How can levers be used?

To exert a force that is greater than the effort.


How do you work out moment?

Moment=force X perpendicular distance from the line of action of the force to the pivot.


What are gears used for?

To change the moment of a turning effect


How do you increase the moment of a turning effect?

A small gear wheel needs to drive a larger gear wheel.


How do you get a low turning effect?

A large gear wheel needs to drive a small gear wheel


What is the centre of mass?

Is the point at which its mass can be thought of as being concentrated.


What happens when the object is suspended ?

It comes to rest with the centre of mass directly below the point of suspension.


Where is the centre of mass in a symmetrical object?

Where all the lines of symmetry meet is where the centre of mass is.


What is the principle of moment?

The sum of the clockwise moment of any point = the sum of the anticlockwise moment of this point.

W1D1 = W2D2


What is the parallelogram of forces?

A scale diagram of two force vectors. It is used to find out the resultant of two forces that do not act along the same line.


What does resolving a force mean?

Finding perpendicular components that have a resultant force that is equal to the force.