Forces

Question 1

Do objects have forces?

Answer 1

Objects don’t have forces they experience them

Question 2

Do heavier objects accelerate faster than lighter objects?

Answer 2

Yes but only if air resistance is present

Question 3

What is the formula for weight?

Answer 3

w=mg
weight= mass(acceleration due to gravity)

Question 4

What is the formula for acceleration?

Answer 4

a=F/m
acceleration=Force/mass

Question 5

If the forces of an object are balanced what can be said about the motion of the object?

Answer 5

The object is either at rest or moving at a constant velocity

Question 6

How do you tell things about an object’s velocity from a free body diagram?

Answer 6

If the pushing force is greater than the frictional force, the net force is not zero, and the crate will accelerate (increase its velocity).
If a crate is being pushed horizontally, and the pushing force is equal and opposite to the frictional force, the net force is zero, and the crate will move at a constant velocity.

Question 7

What is true about Inertia and Mass?

Answer 7

Inertia=Mass

Question 8

What does Inertia not have to do with?

Answer 8

Weight

Question 9

What is the formula for force?

Answer 9

F=ma
Force=mass(acceleration)

Question 10

What is the formula for mass?

Answer 10

m=F/a
mass=Force(acceleration)

Question 11

What causes a stronger gravitational force?

Answer 11

More mass

Question 12

Why do all objects fall with the same acceleration?

Answer 12

All objects on earth fall with the same acceleration because although larger objects have more gravitational force acting on them because of their mass that same large mass gives them a large amount of inertia
a=F/m (similar triangles)
24/12=3/1
45/15=3/1

Question 13

If the net force of an object is 0 then what can you tell about that object?

Answer 13

That the acceleration of that object is 0

Question 14

If an object is moving at a constant velocity on a rough surface what can be said about the force of friction and the driving force of the object?

Answer 14

That they are equal in magnitude

Question 15

Weight

Answer 15

Gravity force acting on an object, always pulls down, W or Fg

Question 16

Normal Force

Answer 16

Support force acting on an object, pushes up, balances gravity, Perpendicular to the surface (only if an object is on a surface) Fn

Question 17

Tension

Answer 17

Rope or string force acting on an object, rope forces always pull, never push, balances weight, Ft or T

Question 18

Friction

Answer 18

Rubbing resistance force acting on an object, always oppose motion, Ff

Question 19

Drag/Air resistance

Answer 19

Air resistance or water resistance acting on an object, always opposes motion

Question 20

Applied force

Answer 20

A person’s push force, only applies when an object is physically being touched, Fa

Question 21

Spring

Answer 21

Force that wants objects to return to their natural length
l=length
l-x= When object shrinks
l+x= When object expands

Question 22

Newton’s 1st Law

Answer 22

A body’s natural state is to be at rest or moving at a straight line at constant speed. In short an object’s natural state is to be at constant velocity. Objects don’t resist motion they resist change in motion.

Question 23

What is an object’s resistance to change in motion called?

Answer 23

Inertia

Question 24

Equilibrium

Answer 24

a net force on the object is 0

Question 25

Static Equilibrium

Answer 25

Equilibrium for an object that is not in motion ex: a book at rest on a table

Question 26

Dynamic Equilibrium

Answer 26

Equilibrium for an object that is in motion ex: an airplane traveling at constant velocity

Question 27

Newton's second law

Answer 27

the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass a larger force will cause a greater acceleration, while a heavier object will accelerate less for the same force F=ma a=F/m m=F/a

Question 28

What does a scale in an elevator read?

Answer 28

Normal force

Question 29

What would a scale in an elevator read if you were traveling at constant velocity?

Answer 29

Weight

Question 30

How does your weight feel in an elevator when traveling at constant velocity?

Answer 30

Weight feels same

Question 31

What happens to normal force when you are accelerating in an elevator?

Answer 31

There is a change in normal force (tug of war between a due to motion usually up and a due to gravity always down)

Question 32

What are equations for Fn?

Answer 32

Fn= mass(a due to gravity + a due to motion) Fn=weight + Fnet if a is positive or Fn=weight-Fnet if a is negative bc Fnet=mass(a) mass will always be positive so Fnet will always be same direction as a

Question 33

When do you feel heavier while traveling in an elevator?

Answer 33

If you are going down slowing down or going up speeding up (a is upward)

Question 34

When do you feel lighter in an elevator?

Answer 34

If you are going down speeding up or going up slowing down (a is downward)

Question 35

Will the force of gravity be greater on objects with greater mass?

Answer 35

Yes because on earth all objects accelerate at the same rate and Fnet=ma or W=mg so the greater the mass with the same acceleration would result in more weight

Question 36

Why would all objects have the same acceleration due to gravity, neglecting air resistance?

Answer 36

Because bigger objects have more inertia and therefore more resistance to change in motion

Question 37

Explain why the earth and moon exert forces of the same magnitude on each other using an equation

Answer 37

Fg=Gm1m2/d^2 bc you're solving for one force of gravity for 2 masses not 2 forces, therefore the forces should be equal

Question 38

What is the action reaction pair of you pushing on a wall?

Answer 38

Action force: You push right on wall Reaction force: wall pushes you to left

Question 39

What is the English test?

Answer 39

given the action force to write the reaction force, switch the noun and reverse the direction

Question 40

What is Newton's third law?

Answer 40

For every action their is an equal and opposite reaction

Question 41

If a fly collides with the windshield of a bus which object has the greater acceleration?

Answer 41

The fly has a much greater a and much low m and the bus has a much greater m and much lower a this is bc they are ultimately exerting an equal and opposite force on each other so their a and m must be inversely proportional

Question 42

What is another equation for Fnet?

Answer 42

Fnet= (upward force-downward force) + (rightward force-leftward force) depends on which direction object is moving, opposite if its going down or left