Work
This type of energy is associated with the motion of an object.
Kinetic Energy
What law is this?
"The momentum of a closed, isolated object or system of objects does not change."
Law of Conservation of Momentum
Impulse: F * t = m * (change in velocity)
For a constant force, if the duration of impact upon an object is doubled, the impulse is (doubled, halved).
doubled
What's the primary difference between elastic and inelastic collisions?
Kinetic energy (is / is not) conserved in inelastic collisions but (is /is not) conserved in collisions.
Kinetic energy IS NOT conserved in inelastic collisions but IS conserved in elastic collisions.
This principle states that energy cannot be created nor destroyed.
Law of Conservation of Energy
The energy stored in an object due to its position in a gravitational field is called this.
gravitational potential energy
In an elastic collision, objects bounce off each other (with, without) deforming or losing energy.
without
Based on impulse:
Impulse: F * t = m * (change in velocity)
Why are car dashboards, steering wheels, and boxing gloves padded?
The pads increase the amount of time, which decreases the force.
true or false? A screw is a type of inclined plane.
true
True or false? An upward force is applied to a bucket as it is carried 20 m across the yard. This is an example of work being done.
False, the force exerted is not causing the displacement
The equation for momentum is p = mv. The units for inertia are:
kg m/s
In an inelastic collision, objects bounce off each other (with, without) deforming or losing energy.
with
Using the definition of impulse:
Impulse: F * t = m * (change in velocity)
How can a karate "chop" break a board?
The time to "chop" is very small, which means the force must be great.
Types of Mechanical Energy:
1. _______ : energy due to an object's motion.
2. _______ : stored energy due to an object's position.
1. Kinetic
2. Potential
True or false? Power refers to how fast work is done upon an object.
True, power is work/time
Impulse equation is
impulse F * t = m * change in velocity
A change in ______________ creates an impulse.
momentum
_________________ is conserved in all types of collisions.
Momentum
Conservation of Momentum:
A prospector finds himself holding his bag of gold and standing in the middle of a large pond of frictionless ice. How can he get to the side before he freezes?
He could throw the bag of gold. While at rest, the momentum is zero. So if he throws the bag, he must move in the opposite direction so that the total momentum will remain constant (equal to zero).
What Law is this?
"Energy can change form but cannot be created or destroyed."
Law of Conservation of Energy
Is work being done on the box? yes or no
1. Student pushes box horizontally across the lab table.
2. Student picks the box up vertically.
3. Student holds the box still.
4. Student holds box still as he walks across room.
1. yes
2. yes
3. no
4. no
Consider which would do more damage - stopping a truck, moving at 60 mph by running into a brick wall, or a haystack?
F * t = m * (change in velocity)
Fill in the blanks below: The _____ and change in _____ of the truck are held constant. To decrease force, the ______ it takes the truck to stop must be (larger or smaller).
The _mass_ and change in _velocity_ of the truck are held constant. To decrease force, the _time_ it takes the truck to stop must be _larger_.
momentum = mass * velocity
Two cars, one twice as heavy as the other, move down a hill at the same speed. Compared to that of the lighter car, the momentum of the heavier car is (double, half) as much.
double
What is the Law of Conservation of Momentum?
For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision.
Kinetic Energy is the energy an object has because of its:
a. location
b. density
c. speed
d. tension
c. speed
Work is done on an object only if the force and displacement are in the _______ ___________.
same direction