Newton's First Law
This fundamental property of matter measures an object's resistance to any change in its motion
Inertia
If mass stays constant and the net force applied to an object triples, what happens to its acceleration?
It triples
Newton's third law states that for every action, there is an equal and opposite ______
Reaction
Friction is a contact force that always acts in what direction relative to an object's sliding motion?
Opposite
On Earth, what do we call the downward gravitational force acting on an object's mass?
Weight
According to the first law, if an object is moving at a constant velocity, what must the net force acting on it be?
Balanced
A 3kg block accelerates at 4m/s2 what is the net force acting on it?
12N
True or False: Action-reaction force pairs always act on the same exact object
False
A box is pushed right with a 40 N while friction pushes left with 15N. What is the net force?
25 N
A book rests flat on a desk. The desk pushes up with a normal force of 15N. What is the gravitational force on the book?
15N
When a vehicle suddenly brakes, why do unbuckled passengers keep moving forward?
Inertia
An object experiences a net force of 50 N and accelerates at 10 m/s2. What is its mass?
5kg
When you jump upward, you push down on the ground. What does the ground do in response, allowing you to lift off?
Pushes back up on you.
If two opposing force acting on a horizontal object are completely equal in magnitude, the forces are considered _______
Balanced
When a falling object reaches terminal velocity, air resistance equals gravity and the net force becomes _________
Zero (meaning they are balanced)
Out of a feather, baseball, bicycle, and a boulder which one possesses the highest inertia?
A boulder
If you double an object's mass while cutting its applied net force in half by what factor does its acceleration change?
A hammer strikes a glass bottle. How do the forces the hammer exerts on the bottle and the bottle exerts on the hammer compare?
They are equal
A 10 kg crate is pushed with 50 N of force against a 20 N frictional force. What is its acceleration?
3 m/s2
An object travels in a circle at the same speed. Explain why this is considered accelerating.
An object is constantly changing direction
If an object is drifting in deep space far away from any gravity or friction, how much net force is required to keep it moving at a constant speed?
0
A constant force pushes a 5 kg object from rest, causing it to travel 10 meters in 2 seconds. What is the magnitude of the applied force?
25N
A bug splatters against the windshield of a speeding bus. During the collision, which experiences a greater magnitude of force: the bug or the bus
Neither, they experience equal forces
A 20 kg sled is pulled across snow with a force of 80 N. If its acceleration is measured at 2m/s2, what is the magnitude of the frictional force opposing it?
40 N
20kg x 2 m/s2 = 40 N. Since you pull with 40 N, friction must be 80 N- 40 N = 40 N
A 5kg textbook is lifted straight upward with an applied force of 70 N. Use g = 10m/s². What is the acceleration?
4 m/s2 upward.
weight = 5kg x 10 m/s2 = 50 N down. Net force =70 N up - 50 N down, which is 20 N up. Acceleration = 20 N / 5kg = 4m/s2
A 20kg cart starts from rest on a frictionless surface. A constant horizontal force of 60N is applied to it for 3 seconds. Calculate the cart's final velocity after 3 seconds.
9m/s
Acceleration is 60N/20kg = 3m/s2.
Final velocity = acceleration x time.