Ruth Ruano, Emily Guevara, Ivana Dominguez - Gravitational Motion, Rotational Motion, Work, Energy Flashcards
What is the equation for gravitational force and what variable is the gravitational constant?
F = G (Mm/r^2), G is the gravitational constant
What is Rotational Motion? - Remember
The motion of an object around a circular path, in a fixed orbit.
What is Earth’s gravitational pull and how do you calculate it?
- mass= 5.973 x 10^24 kg
- radius= 6.378 x 10^6 m
F1 = F2
= (6.67 x 10^-11) (5.973 x 10^24 kg/6.378 x 10^6 m)
= 9.8 m/s^2
If there is more mass, there will be ________ gravity.
more
What is motion? - Remember
The phenomenon in which an object changes its position.
On a space expedition, an astronaut lands on a new planet, where the gravity is -1.56 m/s^2. If his mass is 20 kg, what is his weight?
F of weight = ma of gravity
F of weight = (20 kg)(-1.56 m/s^2)
F of weight = -31.2 N
If Jessica’s weight is -550 N on earth, what is her mass?
F of weight= ma of gravity
-500 N = m(-9.8 m/s^2)
m = (-500 N/-9.8 m/^2)
m = 51.02 kg
What are the units of rotational acceleration?
rad/s^2
What is the definition of energy? (Remember) Daniela Ruano
the ability to do work
What is the definition of Kinetic Energy? (Remember) Daniela Ruano
energy of an object’s motion due to the object’s motion
What is the equation for Kinetic Energy? What does “m” represent in the equation? (Identify) Daniela Ruano
KE = 1/2 m v^2; “m” is the mass of the object
You serve a volleyball with a mass of 2.1 kg. The ball leaves your hand at 30m/s. Calculate the Kinetic Energy of the ball. (Calculation Question) Daniela Ruano
What do we know?
KE= ?
m= 2.1kg
v= 30m/s
Calculation: KE=12(2.1)(30^2) KE=12(2.1)(900) KE=1.05(900) KE=9.45J
Alexa, the platform diver for the McDonald Brothers’ Circus had a kinetic energy of 10,000J just prior to hitting the bucket of water. If Alexa’s mass is 50kg, what was her velocity? (Calculation Question) Daniela Ruano
What do we know?
KE= 10000J
m= 50kg
v= ?
Calculation: KE=12(m)(v^2) 10000=12(50)(v^2) 10000/25=25v^2/25 400=v^2 v=√400 v=√20
What is the definition of Potential Energy? (Remember) Daniela Ruano
Energy that is stored in an object
What is the equation for Potential Energy? What does “g” represent in the equation? (Identify) Daniela Ruano
PE= mgh; “g” represents the acceleration due to gravity
There is a bell at the top of a tower that is 45m high. The bell weighs 190N. The bell has Potential energy. Calculate it. (Calculation Questions) Daniela Ruano
What do we know?
PE= ?
N=190
h= 45
Calculation:
PE=(N)(h)
PE=190(45)
PE=8550J
A 90kg refrigerator is located on the 70th floor of a skyscraper. This skyscraper is 300m above ground. What is the potential energy of the refrigerator?(Calculation Questions) Daniela Ruano
What do we know? PE= ? m= 90 g= 9.8 h= 300
Calculation:
PE=(m)(g)(h)
PE=(90)(9.8)(300)
PE=264600
Identify each component of the Mechanical Energy equation. (Identify) Daniela Ruano
Equation:
ME= KE+PE
Mechanical Energy= Kinetic energy + Potential Energy
A ball has 17J of kinetic energy and its mechanical energy is 25J. Find the potential energy of the ball. (Calculation Question) Daniela Ruano
PE=ME-KE
PE=25-17
PE=8J
What is the definition of work? (Remember) Daniela Ruano
a change in energy produced by a force applied causing a displacement
What is the equation for Work? What does “F” mean? (Identify) Daniela Ruano
W= F*d; “F” represents force
How much work is required to pull a sled 5 meters if you use 60N of force?
(Calculate Question) - Daniela Ruano
Work = Force * Distance Work = 60N * 5m Work = 300 J
