Ruth Ruano, Emily Guevara, Ivana Dominguez - Gravitational Motion, Rotational Motion, Work, Energy

Question 1

What is the equation for gravitational force and what variable is the gravitational constant?

Answer 1

F = G (Mm/r^2), G is the gravitational constant

Question 2

What is Rotational Motion? - Remember

Answer 2

The motion of an object around a circular path, in a fixed orbit.

Question 3

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

Answer 3

F1 = F2
= (6.67 x 10^-11) (5.973 x 10^24 kg/6.378 x 10^6 m)
= 9.8 m/s^2

Question 4

If there is more mass, there will be ________ gravity.

Answer 4

more

Question 5

What is motion? - Remember

Answer 5

The phenomenon in which an object changes its position.

Question 6

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?

Answer 6

F of weight = ma of gravity
F of weight = (20 kg)(-1.56 m/s^2)
F of weight = -31.2 N

Question 7

If Jessica’s weight is -550 N on earth, what is her mass?

Answer 7

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

Question 8

What are the units of rotational acceleration?

Answer 8

rad/s^2

Question 9

What is the definition of energy? (Remember) Daniela Ruano

Answer 9

the ability to do work

Question 10

What is the definition of Kinetic Energy? (Remember) Daniela Ruano

Answer 10

energy of an object’s motion due to the object’s motion

Question 11

What is the equation for Kinetic Energy? What does “m” represent in the equation? (Identify) Daniela Ruano

Answer 11

KE = 1/2 m v^2; “m” is the mass of the object

Question 12

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

Answer 12

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

Question 13

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

Answer 13

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

Question 14

What is the definition of Potential Energy? (Remember) Daniela Ruano

Answer 14

Energy that is stored in an object

Question 15

What is the equation for Potential Energy? What does “g” represent in the equation? (Identify) Daniela Ruano

Answer 15

PE= mgh; “g” represents the acceleration due to gravity

Question 16

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

Answer 16

What do we know?
PE= ?
N=190
h= 45

Calculation:
PE=(N)(h)
PE=190(45)
PE=8550J

Question 17

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

Answer 17

What do we know? 
PE= ?
m= 90
g= 9.8
h= 300

Calculation:
PE=(m)(g)(h)
PE=(90)(9.8)(300)
PE=264600

Question 18

Identify each component of the Mechanical Energy equation. (Identify) Daniela Ruano

Answer 18

Equation:
ME= KE+PE
Mechanical Energy= Kinetic energy + Potential Energy

Question 19

A ball has 17J of kinetic energy and its mechanical energy is 25J. Find the potential energy of the ball. (Calculation Question) Daniela Ruano

Answer 19

PE=ME-KE
PE=25-17
PE=8J

Question 20

What is the definition of work? (Remember) Daniela Ruano

Answer 20

a change in energy produced by a force applied causing a displacement

Question 21

What is the equation for Work? What does “F” mean? (Identify) Daniela Ruano

Answer 21

W= F*d; “F” represents force

Question 22

How much work is required to pull a sled 5 meters if you use 60N of force?
(Calculate Question) - Daniela Ruano

Answer 22

Work = Force * Distance
Work = 60N * 5m
Work = 300 J