Newton's First Law
What does Newton's first law say?
an object at rest remains at rest / an object in motion stays in motion UNLESS an unbalanced force is acted upon it
what is newton's second law? mention units!
f = m x a // a = f/m
f = N, m = kg, a = m/s/s
describes the relationship between force, acceleration, and mass
What is Newton's 3rd law?
every action has an equal and opposite reaction
What is gravity? What exerts this force?
Gravity is a force that pulls objects with mass towards one another
Everything with mass exerts gravity.
The units of acceleration are:
m/s2
what is friction and how is it related to newton's first law (especially on earth?)
friction is the sliding of two objects past one another, on earth friction is the force that usually causes moving objects to eventually stop moving
a boat with a mass of 60 kg experiences a force of 15N to the east, what is the boat's acceleration?
The boat's acceleration is 0.25 m/s/s to the east
How does Newton's Third Law describe why you feel your desk pushing into your hand when you push on your desk?
Any action has an equal and opposite reaction, when you push on the desk your force enters the desk. at the same time the desk is exerting a force of equal strength into your hand according to newton's 3rd law
what is weight, what is mass? Are they the same?
weight is the force of gravity
mass is how much matter is in something
they are NOT the same
When are the 3 times the velocity of an object may change? // When are the 3 times acceleration occurs?
1. slowing down
2. speeding up
3. changing direction
This occurs whenever an object is acted upon by an unbalanced force.
acceleration, change in motion
what is the relationship between force + acceleration? what is the relationship between mass + acceleration?
as force increases, acceleration increases
as mass increases, acceleration decreases
you are stranded in space and drifting away from your space shuttle at a constant velocity. How do you get back to your space shuttle?
throw something in the opposite direction of where you want to go. because of newton's third law, you will be propelled in the opposite direction
what are the two instances that impact objects' gravitational force? How do they impact the force?
larger mass of the objects = more gravity
more distance between the objects = less gravity
A car accelerates from rest to a velocity of 30 meters per second in a time frame of 6 seconds. Calculate the car's acceleration during this time.
5 m/s²
When you're riding in a car that suddenly stops, why do you tend to keep moving forward, and what's the scientific explanation for your seatbelt's role in this situation?
your body is still moving because of newton's first law, and the seatbelt's purpose is to provide a force to slow your motion gradually, preventing injury
If a ball is moving with a force 49 Newtons and has an acceleration of 7 m/s2, what is the ball's mass?
7 kg
a bug and an 18-wheeler truck collide on the highway. Your friend says that because the bug explodes it receives a greater force than it exerts on the truck. Is your friend correct?
no - the truck and the fly exerted the same force on one another. the reason the fly explodes is because it's mass is way smaller + the force has little impact on the truck
What is the mass of a person who weights 441N?
(hint: what is weight?, what is the acceleration of gravity on earth?)
45KG
weight = force = 441N
acceleration on earth = 9.8 m/s/s
use newton's 2nd law!
A sled reaches a constant velocity of 10m/s as it slides across an icy/smooth patch of snow.
Are the forces acting on this sled balanced or unbalanced? how do you know?
balanced, because there is no change in velocity (aka acceleration)