8B Forces Flashcards
State two examples of contact forces.
Friction, air resistance, tension, normal contact force, and Upthrust
State two examples of non-contact forces.
Magnetism, gravity, and electrostatic force.
What is resultant force?
The overall force acting on an object.
What do the arrows on a free body diagram show us?
The direction of the forces acting on an object.
What are balanced forces?
Forces equal in size, acting in opposite directions.
Define equilibrium.
The forces acting on an object are balanced.
Describe the effect of zero resultant force on a stationary object.
It remains stationary
Describe the effect of zero resultant force on a moving object.
It remains at a constant speed.
Define what a frictional force is.
A force that acts in the opposite direction to the movement of an object.
What is drag?
A frictional force where one of the surfaces is a fluid (a liquid or gas).
Give an example of useful frictional force.
Friction between tyres and breaks.
Give an example of unhelpful frictional force.
Air resistance on moving objects
What is streamlining?
Changing the shape of an object to reduce drag.
Describe how penguins are streamlined to swim through the water.
The penguin has a specific shape that means it moves through the water easily.
Describe how cyclists reduce drag during races.
They have streamlined helmets and crouch low to reduce drag.
Why is it useful for racing cars to be streamlined?
So that they can move faster.
Define deformation.
When something changes shape.
What is the difference between elastic and inelastic deformation?
Elastic- an object returns to its original shape after a force is removed, inelastic does not.
How does compression affect an object?
Squashes it.
How does tension affect an object?
Stretches it.
Describe how force and extension are directly proportional for springs.
When an increasing force is applied, the extension increases at the same rate.
What does spring constant tell us about an object?
How much force it would take a spring to stretch a certain distance.
Give one use for elastic materials.
Sports clothing
Give one use for brittle materials.
Building materials.
What is an elastic material?
When an object is deformed by returns to its original shape when the force is removed.
What equipment is required when investigating the elasticity of a material?
Clamp and retort stand, ruler, weights, spring and weight holder.