Chapter 3: Part 1 Flashcards
What is a force?
A push or pull that act on an object
What are the two ways in which forces affect objects?
- Changing the shape of an object (stretching/squashing/deforming)
- Moving the object (acceleration, deceleration, change in direction)
When can a zero net force occur?
Forces can be balanced, such as when you carry an object
What are the three types of forces?
Gravitational force, weight force, friction
Why does no movement occur when a person is standing on the ground
The weight and ground reaction forces are equal in size but opposite in direction, thus the resultant force acting on the body is zero
What is gravity?
A constant force that acts through the centre of mass of an object towards the Earth, causing objects to fall
What is mass?
The amount of matter an object is made up of
What is the equation for weight?
Mass x Gravity
When does friction occur?
When two surfaces are in contact with each other, opposing the motion of an object
What must occur to start an object moving across a surface?
You must first overcome friction by applying an increasingly greater force
What is rolling friction?
The friction present between a rolling object and a flat surface
What is sliding friction?
The friction between two moving surfaces
How do flat tyres on a bike hamper performance?
Flat tyres increase the rolling friction between the tyres and the ground, meaning a greater force is required to overcome the friction and propel the bike forwards
How do weightlifters manipulate friction to improve performance?
They use chalk to increase the friction between the bar and their hands
How do ballroom dances manipulate friction to improve performance?
They wear shoes with highly polished soles and dance on a polished floor, to reduce the friction between their shoes and the floor
