P5 Contact and Non-Contact Forces (page 201) Flashcards
What is a Force?
Frce is a vector quantity
Vector quantities have what?
a magnitude and a direction.
Lofs of physical quantities are vector quantities, give examples?
Vector quantities:
force, velocity, displacement, acceleration, momentum, etc.
Some physical quantities only have what? and what are these called?
only have magnitude and no direction.
They are called scalar quantties.
Give examples of Scalar quantities?
speed, distance, mass, temperature, time etc.
How are Vectors usually represented by? explain why?
An arrow - the length of the arrow shows the magnitude, and the direction of the arrow shows the direction of the quantity.
Veloity is a what quantity?
Vector
speed is a what quantity?
scalar quantity
Look at diagram 2 on page 201, Both bikes are travelling at the same speed v. (the length of each arrow is the same).
Why do they have different velocities?
because they are travelling in different directions.
Can forces be contact or non-contact, or both?
both.
A force is a push or a pull on an object that is caused by what?
by it interacting with something.
(all forces are either contact or non-contact forces).
When two objects have to be touching for a force to act, what is that force called?
a contact force.
give examples of contact force?
e.g. friction, air resistance, tension in ropes, normal contact force, etc
If the objects do not need to be touching for the corce to act, what is the force called?
the force is a non-contact force.
Give examples of non-contact force?
e.g. magnetic force, gravatational force, electrostatic force, etc.
When two objects interact, what do this mean?
there is a force produced on both objects.
What is an interaction pair?
it is a pair of forces that are equal and opposite and act on two interacting objects. (This is basically Newton’s Third Law - see page 212).
The Sun and the Earth are attracted to each other by what force? explain why?
by the gravitational force.
This is a non-contact force. An equal but opposite force of the attraction is felt by both the Sun and the Earth
(the sun is attracted to the Earth, and the Earth is attracted to the Sun).
A chair exerts a force on the ground, whilst the ground pushes back at the chair with the same force (the normal contact force) explain what this means?
Equal but opposite forces are felt by both the chair and the ground.
(the chair pushes on the ground, and the ground pushes on the chair).
A tennis ball is dropped from a height. Name one contact force and one non-contact force that act on the ball as it falls. (2 marks)
Contact force: air resistance (1 mark)
Non-contact force: gravitational force (1 mark)
Name two examples of:
a) a scalar quantity
b) a vector quantity
(4 marks)
Any two from: e.g speed/distance/mass/temperature (2 marks)
