2.2: Newtons Law Flashcards
State Newton’s First Law.
An object will remain at rest or in uniform motion in a straight line unless acted upon by an external resultant force.
State Newton’s Second Law.
Resultant Force = Mass x Acceleration
State Newton’s Third Law.
If body A exerts a force onto body B, body B will exert an equal and opposite force on body A.
What is inertia?
The reluctance of an object to move.
Describe the difference between weight and mass.
Weight is the expression of mass times the gravitational force whereas mass is the constant measure of how much material something is
How strong is the gravitational field strength of Earth?
1 kg = 10N
What is terminal velocity?
The maximum speed in a singular direction an object can go as it cannot accelerate further.
What is air resistance?
Air resistance comes as a result of particles not being able to move away from an object therefore hitting it and slowing it down. A larger surface area will have more air resistance.
Name some examples of resultant forces.
- Friction
- Uplift
- Thrust
- Air resistance
- Push or Pull
- Weight
What is the equation for kinetic energy?
KE = 1/2mv^2
What does the mass of an object dictate?
How easy it is to get the object moving or change its direction - the larger the object the greater the difficulty. This is intertia
What is the effect of balanced forces?
Nothing
What is the effect of unbalanced forces?
Movement or change
What happens if we double the resultant force?
The acceleration doubles
How can you describe the relationship between the resultant force and accelaration?
Proportional
What is the equation for resultant force?
Resultant force = mass x accelaration
What word should you always use in any answer in the Newton’s laws section?
Force
What is mass?
How much stuff something has
What is the gravitational force on earth?
10N
How do you work out the weight of things on earth?
Mass x gravitational field strength (10) = weight (N)
Describe what happens to someone using a parachute to fall
When an object falls, the weight remains constant. Initially the only resultant force on the parachute is their weight so it accelerates downwards. As they speed up the force of air resistance acting upwards on them increases. Eventually, it’s equal and opposite to their weight - the two forces are equal in size but acting in opposite directions so they are balanced. The parachutist continues to fall but now at a terminal and constant speed.
How do forces work on each other?
In pairs
What is the name for the forces that work in pairs?
The action force and the reaction force. They are opposites.
