Force & Motion
What is a force?
A push or a pull that can cause motion
What is the formula for speed?
Speed = Distance ÷ Time
What law says: “An object in motion stays in motion unless acted upon by an outside force”?
Newton's First Law
What kind of energy does a moving object have?
Kinetic energy
What is a device that makes work easier with few or no moving parts?
A simple machine
What word describes a change in position of an object?
Motion
How is velocity different from speed?
It includes direction
What is a common way to write Newton’s Second Law formula?
Force = Mass × Acceleration (note: the original way Isaac Newton wrote it was more complicated, involving math called Calculus, which he co-invented, and momentum, which is related to force!)
What kind of energy is stored due to position or condition?
Potential energy
Name two examples of simple machines.
Any two: lever, wedge, screw, pulley, inclined plane, wheel & axle
What is the name of the force that resists motion between two objects?
Friction
What kind of speed tells us how fast something is going at one moment in time?
Instantaneous speed
According to Newton’s Third Law, if you push on a wall, what happens?
The wall pushes back with equal force
What is the formula for work?
Work = Force × Distance (note: this formula is only true if the force and distance are in the same direction and if the force is constant - otherwise you need Isaac Newton's calculus again which you might learn in college or 12th grade advanced math!)
What kind of machine is made up of two or more simple machines?
A complex machine
True or false. When you push with a force, will it always cause an object to move or change direction?
False (think about pushing on a wall - the wall won't move unless you apply a big enough force)
What do we call a change in speed or direction?
Acceleration
True or False: A bigger force is always needed to move a bigger object.
False.
It could be true, but not necessarily if the bigger object has less mass (e.g. a big balloon is easier to move with a smaller force than a smaller but dense bowling ball). So false.
What law says energy is never created or destroyed?
Law of Conservation of Energy
What two simple machines make up a guillotine, used to um, cut fruit with style?
A pulley and a wedge
What is the term for the tendency of an object to resist a change in motion?
Inertia
You’re on a bike and turn left while staying the same speed. Are you accelerating?
Yes - changing direction is produced by an acceleration in physics!
An ice skater pushes off the wall and slides backward. Which Newton’s Law explains this?
Newton's Third Law
A rock on a cliff falls and starts moving. What energy transformation happens as it falls before it hits the ground?
(Gravitational) Potential Energy → Kinetic Energy
What kind of simple machine is a ramp?
Inclined plane