Types of Forces
What is the unit of measurement for force?
Newton
What is Newton’s First Law of Motion also known as?
The law of inertia.
What is the acceleration due to gravity on Earth, rounded to one decimal place?
9.8 m/s2
What is the formula for calculating force?
f = m x a
What is the formula for momentum?
p = m x v
What type of force resists the motion of objects sliding past each other?
Sliding Friction
According to Newton’s Second Law, what happens to an object when a net force acts on it?
it accelerates in the direction of the net force
What happens to your weight if you travel from Earth to the Moon?
It decreases due to the weakness of the moon's gravity.
If a force of 30 N is applied to a 3 kg object, what is its acceleration?
10 m/s2
What does the Law of Conservation of Momentum state about collisions?
the total momentum before and after a collision remains the same
What is the name for the force that opposes the motion of an object moving through air?
Air Resistance.
What does Newton’s Third Law state about forces between two objects?
for every action, there is an equal and opposite reaction
What is the difference between mass and weight?
mass is the amount of matter and does not change with location, while weight is the force of gravity on an object and can change
A two kilogram object is moving with a velocity of three meters per second. What is its momentum?
6 kg*m/s
What happens to momentum in a collision between two objects?
momentum is transferred between the objects; all momentum is conserved
What 3 factors increase the strength of friction between two surfaces?
rougher surfaces, larger surface area, and greater force pressing them together
Give an everyday example of Newton’s First Law in action.
Ex: your body continuing to move forward when a car stops suddenly
According to the Law of Universal Gravitation, what two factors determine the strength of gravitational attraction between two objects?
mass and distance
What must you do to the units of mass and distance before solving force problems?
Make sure that all mass measurements are in kilograms and all distance measurements are in meters.
If a 22.3 kg object moves at 12.2 m/s, what is its momentum?
~272.06 kg*m/s
If it took a 50 kg object 22 seconds to accelerate from 5.5 m/s to 105 m/s, what was the force being exerted on that object?
~226.14 N
If a 10 kg object accelerates at 2 m/s2, what is the net force acting on it?
20 N
If an object has a mass of fifty kilograms, what is its weight on Earth?
490 N
If the net force on an object is zero, what can you say about its motion?
it will not accelerate; it will remain at rest or move at constant velocity
In a period of 5 seconds, two objects collide: a 3 kg object that has accelerated to 2 m/s from rest, and a 2 kg object at rest. After the collision, the 3 kg object stops. What is now the velocity of the 2 kg object, assuming all momentum is conserved?
3 m/s