Estefania Alvarez, Alessandra Gomez, Alejandra Cardona Flashcards
What is work?
a force applied through a displacement
How can work be calculated?
W=(F)(S)
A 52.0-kg skater moves at 2.5 m/s and stops over a distance of 24.0 m. Find the skater’s initial kinetic energy. How much of her kinetic energy is transformed into other forms of energy by friction as she stops? How much work must she do to speed up to 2.5 m/s again?
1/2 mv^2
=1/2(52.0Kg)(2.5 m/s)^2 =160J
Speed Up
= 1/2(52.0Kg)(2.5 m/s)^2 - 1/2(52.0 kg)(0.00m/s)^2=+160J
An 875.0-kg car speeds up from 22.0 m/s to 44.0 m/s. What are the initial and final kinetic energies of the car?
=1/2 mv^2
Initial Ki
Ki= 1/2(875.0kg)(22.0)^2 =2.12x10^5 J
Final Ki
1/2(875.0kg)(44.0)^2 =8.47 10^5J
What is gravity? .
A force that attracts all objects toward each other
What is inertia .
The tendency of an object to resist a change in motion
Newton first law of motion .
an object at rest will stay at rest and an object in motion will stay in motion
What is the ‘g’ value? .
g=GM/R^2
What is Energy?
Science Usage
the ability of a system to produce a change in itself or the world around it
Common Usage
the capacity of acting or being active
A students walks 100 m in 70 sec. What is the students speed? .
s=1.4m/s
What does the gravitational depend on? e
the mass of each object and the distance between the centers of the two objects.
What is the Mechanical Energy of System equation?
ME=KE+PE
what is the law of universal graviton? e
all objects in the universe attracts other object
Gravitational potentional energy formula, measured in Joules (J)? .
Eg
what two factors determine the strength of the force of gravity between two objects? e
Mass and Distance