Contact Forces
This type of force occurs when two objects physically touch or interact
What is contact force?
The energy an object has because it is moving.
What is kinetic energy?
The maximum force measured during a collision.
What is Peak force?
A change in an object's shape caused by an applied force.
What is Deformation?
Requirements a design must meet.
What is criteria?
A floor pushes upward on a container resting on it. This force is exerted by the floor on the container.
What is upward force? (normal force)
Increasing either of these two variables increases kinetic energy.
What is Mass and speed?
When collision speed increases while mass stays the same, peak force generally_____________.
(decreases, increases, stays the same)
What is increases?
When a material deforms more during a collision, this often happens to contact time.
(decreases/gets shorter, stays the same, increases/gets longer)
What is contact time increases/gets longer?
Limits or restrictions placed on a design.
What is constraints?
In a collision, the two interacting objects exert forces that are equal in _______ and opposite in _________.
What is Equal in strength and opposite in direction?
If the speed of an object increases, its kinetic energy generally ___________.
(decreases, increases, stays the same)
What is increases?
Trial A: 4 kg at 2 m/s → 310 N.
Trial C: 4 kg at 4 m/s → 790 N.
What variable changed?
What is speed?
A longer contact time during a collision often results in a ______ peak force.
What is lower/smaller?
When improving one feature makes another feature less desirable.
What is a trade-off?
A container pushes down on a floor with an amount of force of 520 N. The floor pushes on the container with this amount of force.
What is 520 N?
A 4 kg object moving at 2 m/s has less kinetic energy than the same object at 4 m/s. This shows that speed has a ______ effect.
What is A greater/stronger effect?
Trial D: 2 kg at 3 m/s → 290 N.
Trial E: 4 kg at 3 m/s → 520 N.
What variable changed?
What is mass?
Foam has open, air-filled spaces. During impact, these spaces allow the material to do this.
What is compress/deform?
A design process in which engineers use evidence to modify a solution to improve it.
What is redesign/optimization?
True or false: An object must be moving for a contact force to act on it.
False; a stationary object can still experience a contact force
A data set shows 1 m/s → 2 J, 2 m/s → 8 J, 3 m/s → 18 J, 4 m/s → 32 J. What pattern does this show?
What is kinetic energy increases at a greater rate than speed?
Explain the chain:
greater speed → greater kinetic energy → ______ during the collision.
What is greater peak force?
What causes rigid plastic to produce a higher peak force than foam?
What is shorter contact time and less deformation?
A bumper reduces peak force but becomes too fragile to survive repeated collisions. This is an example of what engineering idea?
What is a trade-off between force reduction and durability?