Friction and Forces
55 N
A child pushes down on a box lid with a force of 25 N. At the same time, her friend pushed down on the lid with a force of 30 N. The spring on the box lid pushes upward with a force of 60 N. What is the net force being applied to the box lid?
balanced forces
Forces acting on an object that combine and form a net force of zero.
unbalanced forces
Forces acting on an object that combine and form a net force that is not zero.
increased mass
How can you increase gravity
You add the forces.
How do you calculate the net force on an object if two forces are action on the object in the same direction?
Balanced forces do not change the motion of an object; unbalanced forces do.
How is motion related to balanced and unbalanced forces?
145 N to the right
Three people push a piano on wheels with forces of 130 N to the right, 150 N to the left, and 165 N to the right. What are the strength and direction of the net force on the piano?
The velocity of the car stays the same.
What happens to the velocity of a moving care if the forces on it are balanced?
50 N to the right
What is the net force on an object if one person applies a force of 100 N to the right and another person applies
Balanced forces cause no change in the motion of objects.
What is the relationship between balanced forces and the motion of an object?
When unbalanced forces act on an object, the object's velocity changes.
What is the relationship between unbalanced forces and the velocity of an object?
The direction of the net force is the same direction as the forces you add together.
When combining forces in the same direction, how do you determine the direction of the net force?
5 N
You push a book sitting on a desk with a force of 5 N, but the book does not move What is the static friction?
friction
a contact force that resists
reference direction
a direction that you choose from a starting point to describe an object's position
noncontact force
a force that one object applies to another object without touching it
force
a push or a pull on an object
contact force
a push or a pull on one object by another object that is touching it
gravity
an attractive force that exists between all objects that have mass
static
at rest or having no motion
inertia
causes an object in motion to remain in motion; inactive
motion
changing position
object at rest
net force is zero: the object will remain at rest
mass
the amount of matter in an object
weight
the gravitational force exerted on an object
object in motion
the net force is zero: the object will remain moving in a straight line with constant speed
net force
the sum of all forces acting on an object