PHYSICS - Forces and Motion Flashcards
What’s weight?
Force due to gravity
What’s friction?
Force that resists motion
What’s resistance?
liek as in air resistance y’know
Drag force as an object tries to move through liquid or gas
What’s the name of the unit of force? (gravity guy)
Newton (N)
What’s mass?
like what is it really?
Amount of matter stuff is made from
What’s the unit of mass?
Kg
Does mass change depending on location?
like on the moon vs earth for example
No, but weight can if the gravity changes
What’s the unit of weight?
N
What’s the equation for weight?
Mass x Gravitational field strength
(field strength’s 10 on earth)
What’s gravity?
force of attraction between masses
What gives weight?
Gravitational attraction
What’s newton’s first law?
“If a body is in a state of rest (stationary) or moving at a constant speed it will continue to do so unless acted on by an external force”
this is also called the law of inertia - 🤓
What’s newton’s second law?
F=ma
If forces on an object are inbalanced, an object will accelerate or decelerate. If force is large, it will accelerate more, but if mass is large, it will accelerate less.
When there are two forces acting on an object in different directions, how do you get the resulting force?
mathemtica;l
It’s the difference between the two forces (minus)
Suppose a guy is on a bridge. The guy’s weight is 100 000N. What force must the bridge supply to support him?
100 000N
What is newton’s third law?
everyone’s favourite
For every action there’s an equal and opposite reaction
suppose a monkey is holding a cardboard box. The monkey weighs 200N, and the box 50N.
What force does the ground react with to support the monkey?
Add Footnote
200 + 50 = 250N
Describe the life journey of a skydiver jumping out of a plane from when he jumps to the parachute opening
1) The only force is weight, so skydiver accelerates downwards
2) As he accelerates, he experiences air resistance and accelerates at a slower rate
3) Eventually air resistance and weight are equal, so he stops accelerating and falls at a constant speed (this is terminal velocity)
4) When the parachute opens, air resistance increases rapidly and the skydiver decelerates downwards
5) As the skydiver decelerates, air resistance also decreases. It becomes equal to the weight again and skydiver now has a new, slower terminal velocity
What’s the name of a force pulling a skydiver to the ground?
it ain’t gravity, bozo
Weight
Without air resistance, how do objects accelerate when dropped?
All objects accelerate the same due to gravity
only without air resistance though
