·
Mass and Weight🤨
- Mass is the amount of matter in an object and it is measured in kilograms (kg).
- Weight is the force of gravity on an object and it is measured in newtons (n).
- On Earth, every kilogram of mass is pulled down with a force of 10 N.
weight (n) = mass (kg) x gravitational field strength (n/kg)
w = m x g
Terminal Velocity😆
- the force of gravity on a large mass is greater than on a small mass but the large mass also needs a greater force to accelerate it.
- the two effects cancel out, and so all masses fall at the same rate in a vacuum.
- this acceleration due to gravity is 10m/s/s on the Earth.
Example of a skydiver...This is a common example given in I/GCSE Physics🪂
- Just after jumping: the skydiver's velocity and air resistance are both very small. The resultant force present is weight and his acceleration is 10m/s/s.
- 5 seconds later: the skydiver's velocity is greater and his air resistance is about half of weight. The resultant force is weight - air resistance.
- About 12 seconds after jumping: the skydiver's velocity is at maximum or terminal velocity and his air resistance is equal to weight. The resultant force is 0 N and his acceleration is 0 m/s/s.
Reference: https://thumbs.dreamstime.com/z/terminal-velocity-vector-illustration-labeled-falling-speed-explanation-terminal-velocity-vector-illustration-labeled-falling-165133631.jpg
Drafted by Catrina (Physics)