Topic 9- forces and their effects Flashcards
What are contact forces?
forces that require touch between objects in order for the force to act
What is the non-contact forces?
Forces that act at a distance. e.g. gravitational, electrostatic and magnetic fields
What causes the gravitational attraction between objects (like the earth and sun)
their gravitational potential strengths interacting
What causes attraction and repulsion between magnetic objects?
Interacting magnetic fields
What causes attraction and repulsion between electrical charges?
Interactions between their electric fields (electrostatic forces)
What does a free body force diagram show?
An isolated body and all of the forces acting on it
What shouldnt a free body force diagram include?
The forces it exerts on the rest of the world
Objects in equilibrium have a resultant force of ….. and are either ……. or moving at a ………………?
- Zero
- Stationary
- Steady speed
Which direction does normal contact force act?
Upwards
What is Newton’s third law?
Whenever two objects interact, both objects feel an equal but opposite force
Describe how you use scale drawings?
- Draw all forces acting on an object to scale, tip to tail
- Draw a straight line from the start of the first force, to the end of the last force. This is the resultant force
3) Measure length of resultant force. (cm - N)
What is a moment?
The turning effect of a force
What would the force on a spanner cause?
A turning effect or moment on the nut
What is the formula to calculate the size of a moment
moment of a force = force *distance
How could you get the maximum moment?
Push at right angles to the object to get the largest distance
