Forces

• Name Newtons 3 laws of motion

  Newton's 1st law tells us that an object won't change its motion unless acted upon by a force. Newton's 2nd law tells us that heavier objects need a larger force to move them (F=ma). Newton's 3rd law tells us that for every action there is an equal and opposite reaction. 
• types of forces

  
• what is the difference between Contact forces and non Contact forces


  Contact force occurs due to the contact between two different objects. Non-contact force occurs due to either attraction or repulsion between two objects such that there is no contact between these objects.

  
• hookes law: Extension happens when an object increases in length, and compression happens when it decreases in length. The extension of an elastic object, such as a spring, is described by Hooke's law:

  force = spring constant × extension


  • force (F) is measured in newtons (N)
  • spring constant (k) is measured in newtons per metre (N/m)
  • extension (e), or increase in length, is measured in metres (m)
• A force of 3 N is applied to a spring. The spring stretches reversibly by 0.15 m - the fact that the string stretches reversibly means that it will go back to its normal shape after the force has been removed. Calculate the spring constant.


  (k=f/e) k=3/0.15=20n/m
• Gravitational fields definition

  All objects with mass produce a gravitational field. The more mass an object has, the greater its gravitational field will be.
• 9.8 is...

  the worlds acceleration due to gravity.