Newtons First Law
When a force is applied to an object, it’ll remain either in motion forever or rest forever- Essentially objects tend to “keep doing what they’re doing” unless a force changes their motion
Newtons 2nd Law
Force applied on a mass of an object equals acceleration
Newton’s 3rd Law
For every action, there is an equal and opposite reaction.
Resultant force is…
overall force
e.g. a skydiver falling weight > air resistance
Terminal velocity is…
maximum velocity- The constant maximum speed an object reaches when (upward) drag force equals (downward) gravity resulting in zero acceleration.
Inertia is…
resistance to change
e.g a tablecloth being pulled from under dishes.
Give three factors that affect friction (3)
Texture
Area
Weight
State Newton’s First Law and give an example (2)
a.k.a ‘Law of inertia’
When force is applied to an object it will remain in either motion or rest forever. If a car stops suddenly, the passengers continue moving forward because of their inertia, often resulting in them being pushed against the seatbelt.
Essentially objects tend to “keep doing what they’re doing” unless a force changes their motion
A trolley is pushed with 25N right, friction 18N left- What is the 1)resultant force
2)direction and 3)effect on velocity (3)
1) 7N (25N - 18N)
2) right
3) acclerates
Describe changes to air resistance on a skydiver until terminal velocity (3)
As the skydiver leaves the plane their speed is relatively low meaning air resistance is small(1)
After sometime the skydiver gains speed and collides with more air molecules, increasing air resistance, as this happens net downward force decreases, so skydiver continues to accelerate at a decreasing rate(1)
Eventually, the speed becomes high enough that the air resistance equals the downward force of gravity(1)
Compare scalar and vector quantities; give 3 examples each and explain why forces are vectors (6)
Scalar - Mass, Distance, Speed.
Vector-Force, Velocity,Displacement.
Forces are vectors because forces require direction
