Vocabulary
What unit is used to measure force?
Newton
How would balanced forces be illustrated with arrows?
The arrows would be the same length/size.
Explain whether you think gravity is a balanced or unbalanced force.
Unbalanced which is why objects are pulled toward the earth instead of hanging in mid-air.
What is Newton's Second Law about?
Force = M x A
The force is determined by the mass and acceleration of an object.
Take two people. One weighs 50 pounds, the other weighs 100 pounds. They both sit in their chair. What is the chair doing?
The chair pushes up with the same force the people push down.
What is the difference between mass and weight?
Mass measures the amount of matter within an object and weight is a measure of the gravitational pull on an object.
What is it called when more than a single force acts on an object at one time?
Net force.
If gravity makes things fall at 9.8 m/s/s, what is "terminal velocity"?
The fastest speed something can fall. It has increased as much as it can, and it can't go any faster.
Manipulate Newton's Second Law three times to show how each variable can be calculated.
F = M x A
M = F/A
A = F/M
What is Newton's Third Law?
For every action there is an equal but opposite reaction.
What happens when an unbalanced force acts on an object?
It changes the motion of the object.
What is term used to describe the force that two surfaces exert on each other when they rub together?
Friction.
If gravity acts on all objects, why do some things fall faster than others? A leaf and a stone, for instance.
Air resistance.
If you want a baseball/softball to accelerate faster, show how you would manipulate the equation to make that happen.
You would increase the force or decrease the mass.
Explain why it is difficult to step off a boat onto a dock.
When you push off the boat to step onto the dock, the boat moves backward with the same force you used to step up. SPLASH!
How are the definition of force and the description of force, different?
The definition is "push or pull".
The description is "the direction and strength or magnitude".
What sort of force is applied to a basketball when two players are fighting for the ball, and it isn't moving.
Balanced force.
Describe Newton's First Law and give an example.
An object in motion or at rest will stay that way unless an unbalance force acts on it.
An arrow shooting through the air. Gravity and air resistance/friction will bring it down.
If you want to calculate which will hurt more, being hit by a ATV going 20 mph or a motorcycle going 10 mph, what would you do?
Multiply the mass times the acceleration to determine the force.
Which has greater momentum, a ball traveling at
20 m/s or a car traveling at 20 m/s?
The car because it has greater mass.
The force that pulls a marble toward a bowling ball.
Gravity
Give an example of the four types of friction.
Static: the friction between objects not moving
Sliding: two solid surfaces slike over each other.
Rolling: something rolling over a surface
Fluid: solid moving through a fluid
What is a term often used to describe Newton's First Law? Give an example.
Inertia.
Pull a table cloth out from under dishes.
Calculate the force it would take to accelerate an 800-kg car at a rate of 5 m/s/s.
4,000 N.
How is Newton's Cradle an example of "Conservation of Momentum"?
One ball's movement is passed to the next and the next. The energy doesn't change, nor does the momentum.