Newton's First Law
What is Newton's First Law of Motion?
This law states that an object will remain at rest or continue moving at a constant velocity unless acted upon by a net external force.
What is Newton's Second Law of Motion?
This law states that the acceleration of an object depends on the net force acting on it and its mass.
What is Newton’s Third Law of Motion?
For every action force, there is an equal and opposite reaction force.
What is weight?
The vertical, downward force exerted on a mass as a result of gravity.
What is the force that causes a chair to slow down after you push it accross the floor.
Friction
What is inertia?
The tendency of an object to resist changes to its motion.
State the equation that relates force, mass, and acceleration.
F=ma
A swimmer pushes water backward, what is the resulting motion of the swimmer?
The swimmer moving forward (or being propelled forward)
What is gravity?
The force of attraction that exists between two masses.
What type of force is responsible for getting an object moving?
Applied force
A passenger lurches forward when a car suddenly brakes because their body tends to continue moving due to this property.
Interitia
A force of 20 N acts on a 4 kg object. Using Newton's Second Law, calculate the object's acceleration.
5 m/s²
A rocket launches by pushing gas downwards. Explain why the rocket moves upward.
The rocket exerts a force on the gas, and the gas exerts an equal and opposite force pushing the rocket upward.
What is the constant number we always use for acceleration when we are calculating our scientific weight on planet Earth.
9.8 (m/s^2)
What is the type of force that opposes gravity when the object is at rest on a surface?
Normal force
A hockey puck slides across smooth ice and continues moving for a long distance. Explain why this does not violate Newton's First Law even though the puck eventually stops.
Friction and air resistance act as external forces, causing the puck to slow and stop
Two shopping trolleys are pushed with the same force. One trolley is empty and the other is full of groceries. Explain why the empty trolley accelerates more.
The empty trolley has less mass, so the same force produces a greater acceleration
A student says, “If forces are equal and opposite, a car and a truck should not move when they collide.” Explain why this reasoning is incorrect.
The action–reaction forces act on different objects, so they do not cancel each other; each object still experiences its own net force and motion changes depending on its mass
Calculate the weight (NUMBER AND UNIT) of a person whose mass is 55 kg and is standing on planet Earth.
539N
What type of force makes objects float?
Buoyant
An astronaut in deep space throws a wrench. After leaving the astronaut's hand, the wrench continues moving at a constant velocity. Explain why this is a better demonstration of Newton's First Law than a rolling ball on Earth.
Deep space has negligible friction and air resistance, so there is essentially no net external force acting on the wrench
A truck and a car experience the same acceleration. Explain which vehicle requires the greater net force and why.
The truck, because its greater mass requires a greater force to produce the same acceleration
When walking, your foot pushes backward on the ground. Explain in detail how Newton’s Third Law allows forward motion, and identify all force pairs involved.
Your foot pushes backward on the ground, and the ground pushes forward on your foot with an equal and opposite force; this forward force propels you forward, and involves multiple interacting force pairs between foot, ground, and friction
What are the standard units used for describing the values of Force, Mass, and Acceleration when using Newton's Second Law of Motion.
Newtons, kilograms, and metres per second per second?
What term is used to describe forces that do not cause acceleration?
Balanced force