Forces and Motion 1
Definition of energy
The ability to do work
A push or pull
Force
Student A is pushing a box with a force of 20N to the right. Student B is pushing with a force of 20 N to the right. Will the box move?
yes to the right!
Which of Newton's Law is the Law of Action-Reaction?
A) 1
B) 3
Newton's Third Law
Stefan pushes a cart with three books so it reaches the end of a track. He puts six books onto the cart. What must he use next time so the cart reaches the end of the track?
a. less force
b. more force
c. the same force
d. a different cart
B. more force
A change in position is called
Motion
Unit of measurement for force
Hint: named after scientist
Newtons
Forces that cause a change in motion are called..
Hint: not equal 8th graders vs 1st graders in tug of war
unbalanced forces
Friction in the air is called...
Air Resistance
Energy can be destroyed
TRUE or FALSE
FALSE
A large rock is motionless on a flat sidewalk. Which statement best explains why the rock remains motionless?
A) There are no forces acting on the rock.
B) The forces acting on the rock are all balanced
B
A force between two surfaces which prevents them from sliding past one another. A force that acts in the opposite direction of the traveling object
Friction
Student A is pushing a box with a force of 20N to the right. Student B is pushing with a force of 25 N to the left. What is the net force of this situation
Hint Subtract
5 N to the left
In a game of tug-o-war, what happens when the forces exerted by Team A and Team B are balanced?
neither team wins
What is Newton's Third Law of Motion?
For every action there is an equal and opposite reaction.
Besides size/magnitude, what does every force have?
Direction
An object that is accelerating can be
described as a(n) _____________ force.
balanced or unbalanced
Unbalanced
Forces on an object that are equal in size and opposite in direction, cancelling each other out are called...
Balanced Forces
As motion increases friction ________.
A) increases
B) decreases
B) decreases
Why would an object in a spacecraft float in air rather than fall to the floor?
a. There is no gravity in space.
b. None of Newton's Laws of Motion applies to space.
c. The force of gravity in space is less than it is on Earth.
d. Inertia allows the object to overcome the force of gravity.
c. The force of gravity in space is less than it is on Earth.
What is the Law of Conservation of Energy?
Energy cannot be created nor destroyed. Just transformed
What is Newton's Second Law of Motion?
A) Action vs Reaction
B) F= m x a
The greater the mass of an object, the more force it will take to accelerate.
F= m x a
What is Newton's First Law of Motion?
A) Action vs Reaction
B) An object at rest will stay at rest
C) D = M\V
An object at rest will stay at rest and an object in motion will stay in motion, unless acted upon by an unbalanced force.
Danielle pulled gently on a spring scale. The scale showed a force, but the block did not move. Why not?
a. The force that she applied was balanced by another force.
b. The string between the spring scale and the block was not strong enough.
c. The spring scale was broken, so there was no force when she pulled on it.
d. There was not enough friction for the block to move.
a. The force that she applied was balanced by another force.
Which of the following objects will have the greatest change in motion?
a. a small force applied to an object with a large mass.
b. a large force applied to an object with a large mass.
c. a large force applied to an object with a small mass.
c. a large force applied to an object with a small mass.