Frames of Reference Practice Solutions
A girl is on a train that is headed East at 100 miles per hour. The girl is walking at 5 miles per hour
toward the back of the train.
1.
What is the speed and direction of the train if the girls is the frame of reference?
Answer:
5 mph East.
Explanation:
If the girl is the frame of reference, we need to check the train's relative movement to the girl.
If the girl was not moving inside the train, the speed of the train would be zero, because the train and the girl would be moving together with the same speed and direction.
If the girl is moving 5 mph toward the back of the train, the movement of the train should be calculated considering the girl is fixed (not moving).
So the direction of the train movement would be the inverse of the girls movement (the girl is going West), then the speed and direction of the train is 5 mph and East.
What protects you from getting a shock when you touch a live wire?
A grounding wire
B circuit breaker
C fuse
D insulation
Answer:
Insulation protects you. Thats because the insulation will make a wall almost where the electrons cannot travel through. So when you touch the insulation on a live wire your SAFE. Insulations may include rubber, wood, and air.
Answer:
I'm pretty sure its insulation
Explanation:
What is the photoelectric effect?
A the absorption of particles by a metal surface that is exposed to red light or infrared rays
B the proportional relationship between a photon's energy and the frequency of light.
C the emission of electrons from a metal caused by light striking the metal
D the ability of specialized photons to bounce off a metal surface.
Answer: C
the emission of electrons from a metal caused by light striking the metal
Explanation:
Photo means anything related to light in Physics and science generally.
Photoelectric effect explains the effect of light incident on metal surfaces by knocking out electrons on the metal surfaces.
The correct option is C
the emission of electrons from a metal caused by light striking the metal
6. How is work related to kinetic energy?
Answer: Energy should be transferred to an object in order to move it. This amount of energy transferred by the force to move an object is called work or work done. Thus, the relation between Work and Energy is direct. That is, the difference in the Kinetic energy of an object is work done by an object. OR
The principle of work and kinetic energy (also known as the work-energy theorem) states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. The kinetic energy of the block increases as a result by the amount of work.
Explanation:
Variations to the forehand stroke are not allowed. True False
Consider a situation where the acceleration of an object is always directed perpendicular to its velocity. This means that
(A) the object is increasing speed.
(B) the object is decreasing speed.
(C) the object is not moving.
(D) the object is turning.
(E) this situation would not be physically possible.
Answer:
this situation would not be physically possible
the skeletal system serves all the following functions except
Answer:
The major functions of the bones are body support, facilitation of movement, protection of internal organs, storage of minerals and fat, and hematopoiesis. Together, the muscular system and skeletal system are known as the musculoskeletal system.
your question seems incomplete. Kindly give the full question so that it helps :)
Answer:
D.
producing ligaments and tendons
Explanation:
If 10,000 J of work was done to raise a 225 kg box, how high was the box raised?
Answer:
Explanation: Work=force×distance
W=F×S where W=10,000J, F=m×g=225 kg×10 N/kg= 2250 N
⇒S=W/F
= 10000/2250
= 4.44 m
The box will be raised 4.53 m
What is work done ?Work done is defined as the product of component of the force in the direction of the displacement and the magnitude of this displacement .
Work done = F .s = Fs cos (theta)
F = mg
s =h
theta = 0°
cos (theta) = cos 0 = 1
hence , work done = m*g*h
Potential energy is stored in the form of work done
potential energy = work done to raise the box = m*g*h
given
mass (m) = 225kg
work done(WD) = 10,000 J
height (h) = ?
potential energy = m*g*h
10,000 J= 225kg * 9.8m/s^2 * h
h = 4.53 m
The box will be raised 4.53 m
learn more about work done
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_______ force can be thought of as either a push or a pull, as long as it
makes the object move in a circular path.
Answer: Centripetal
Explanation: The centripetal force refers to the acting on a body moving in a circular path. This force acts in the direction of the center of rotation. The centripetal force is given by :
F = mv^2 / r
Where m = mass of th body
v. = Velocity
r = radius of the circular path.
For an object to move in a circular path, the force required is called the centripetal force. It is measured in Kgms^-2. It is directly proportional to the product of the Mass and square of it Velocity and varies inversely to the Radius of its path.
If we decrease the amount of force, and keep all other factors the same, what will happen to the amount of work? The amount of work will go down because the distance will decrease. The amount of work will go up because the distance will decrease. The amount of work will go down because the distance will increase. The amount of work will go up because the distance will increase.
Answer:
The amount of work will decrease because force is directly proportional to work
while distance will increase since it is inversely proportional to force.
Answer:c
Explanation:The amount of work will go down because the distance will increase.
Two vectors which do not lie along the same line represent what kind of
motion?
A. Resultant motion
B. Scalar motion
C. One-dimensional motion
D. Two-dimensional motion
In order to increase the speed in a gear system
the driven gear must be larger than the driving gear
the driving gear must be larger than the driven gear
the driving gear must be the same size as the driven gear
none of these
asap plz
plz asap
Answer:
the driving gear must be larger than the driven gear
Explanation:
what type of circuit is shown?
A. open parallel circuit
B. open series circuit
C. closed parallel circuit
D. closed series circuit
Answer:
A. open parallel circuit im pretty sure
Explanation:
Answer:
D
Explanation:
The bulbs are on the same wire as the battery, so its series. Current is flowing so its closed.
Which statement correctly describes gravity?
O an attractive force that acts between all objects through contact
O an attractive force that acts between all objects without contact
O a repulsive force that acts between all objects through contact
a repulsive force that acts between all objects without contact
The second one is best. Gravity is an attractive force that acts between all objects, whether they're in contact or not.
Gravity is an attractive force that acts between all objects, whether they're in contact or not.
What is gravity?Gravity, also called gravitation, in mechanics, is the universal force of attraction acting between all matter. It is by far the weakest known force in nature and thus plays no role in determining the internal properties of everyday matter.
On the other hand, through its long reach and universal action, it controls the trajectories of bodies in the solar system and elsewhere in the universe and the structures and evolution of stars, galaxies, and the whole cosmos.
On Earth, all bodies have a weight, or downward force of gravity, proportional to their mass, which Earth’s mass exerts on them. Gravity is measured by the acceleration that it gives to freely falling objects. At Earth’s surface, the acceleration of gravity is about 9.8 metres (32 feet) per second per second.
Thus, for every second an object is in free fall, its speed increases by about 9.8 metres per second. At the surface of the Moon, the acceleration of a freely falling body is about 1.6 metres per second per second.
Hence Gravity is an attractive force that acts between all objects, whether they're in contact or not.
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A man of mass 60kg climbs up a 20m long staircase to the top of building 10m high. What is the work done by him
Answer:
mass=60kg
h=20m
g=10m/s²
here the work done by the body is equal to its potential energy
work done=P.E.
As we know that P.E.=mgh
putting values
P.E.=60kg×20m×10m/s²
P.E.=1200kgm×10m/s²
P.E.=12000Nm
so the work done by the body is 12000Nm
If earth had two moons, how might this affect the way we see eclipses here on earth?
forms of energy!! matching game PLZ I NEED HELP !!!
What is nuclear energy?
A. Stored energy due to an object's location or position
O.B. Energy carried by moving electrons
O C. Energy due to an object's motion
O D. Energy released from atoms
Answer:
the answer from nod energy from atoms
The part of a circult that increases the electric potential of the electrons is the
Answer:
The part of a circuit that increases the electric potential of the electrons is the battery.
Answer:
Explanation:it is an electromotive force that increases the potential of the electrons.
static electricty is the study of..
A buildup of charge
B electric discharges
C electric fields
D all of the above
Answer:
all of the above
Explanation:
i study this kind of stuff in school
Resistance is a measure of.
a) the energy per unit charge in a circuit
b) how hard it is for electrons to move through the circuit
c) how hard it is for electrons to move through the battery
d) the number of charge carriers in a circuit
A planet has a period of revolution about the Sun equal to Tand a mean distance from the Sun equal to R. T varies directly as _____.
A. R
B. R²
C. R3
D. R4
E. R5
Answer:
C. R3
Explanation:
Answer:
C. R3
Explanation:
Plato
9. A ball is thrown straight up with an initial speed of 30 m/s. How long will it take to reach the top of its trajectory, and high will the ball go?
Answer:
1.) Time t = 3.1 seconds
2.) Height h = 46 metres
Explanation:
given that the initial velocity U = 30 m/s
At the top of the trajectory, the final velocity V = 0
Using first equation of motion
V = U - gt
g is negative 9.81m/^2 as the object is going against the gravity.
Substitute all the parameters into the formula
0 = 30 - 9.81t
9.81t = 30
Make t the subject of formula
t = 30/9.81
t = 3.058 seconds
t = 3.1 seconds approximately
Therefore, it will take 3.1 seconds to reach to reach the top of its trajectory.
2.) The height it will go can be calculated by using second equation of motion
h = ut - 1/2gt^2
Substitutes U, g and t into the formula
h = 30(3.1) - 1/2 × 9.8 × 3.1^2
h = 93 - 47.089
h = 45.911 m
It will go 46 metres approximately high.
Please help me find the last one ASAP! Thanks :))) (You don't have to send the definition)
What other types of energy are present when turning a generator that were not mention in question ? Explain where in the process they are present . ( Types of energy : Heat , light , sound , radiant , chemical
PLEASE HELP!!
Answer:
When an object is in motion, there is energy associated with that object. Why should that be the case? Moving objects are capable of causing a change, or, put differently, of doing work. For example, think of a wrecking ball. Even a slow-moving wrecking ball can do a lot of damage to another object, such as an empty house. However, a wrecking ball that is not moving does not do any work
(hope it helps :p )
A car accelerates uniformly from 0 km/hr to 60 km/hr in 4.5 seconds. Which one of the following choices best represents the acceleration of the car?
(A) 13.3 m/s2
(B) 9.8 m/s2
(C) 4.8 m/s2
(D) 3.7 m/s2
(E) 0.37 m/s2
please show work
Answer:
The acceleration of the car is [tex]3.7\ m/s^2[/tex].
Explanation:
It is given that,
Initial speed of the car, u = 0
Final speed of the car, v = 60 km/h = 16.66 m/s
Time, t = 4.5 s
We need to find the acceleration of the car. It is equal to the change in velocity divided by time taken. It can be given by :
[tex]a=\dfrac{v-u}{t}\\\\a=\dfrac{16.66-0}{4.5}\\\\a=3.7\ m/s^2[/tex]
So, the acceleration of the car is [tex]3.7\ m/s^2[/tex]. Hence, this is the required solution.
2) Light reflects off of surfaces. It is also absorbed by opaque materials
and transmitted through transparent objects. Consider this diagram of
tvo sheets of construction paper. Elaborate on the behavior of the
incident light waves
A)
White paper reflects the incoming waves, while black
absorbs the incoming waves.
White paper reflects some of the incoming waves,
while black absorbs all of the incoming waves.
B)
Q
The white paper absorbs and transmits light waves,
while the black paper absorbs all light waves.
Some of the light waves incident on the white paper
D) are reflected and some are absorbed. None of the
Light waves are reflected from the black paper.
Answer: B
White paper reflects some of the incoming waves,
while black absorbs all of the incoming waves.
Explanation:
Light is reflected off of white surfaces. Light is absorbed by opaque materials and transmitted through transparent objects.
In the case of a white paper, a white paper can be considered as a translucent material in which some of the light incident on it bounces off while some pass through it. Therefore, we can conclude that White paper reflects some of the incoming waves,
while black absorbs all of the incoming waves.
A ball rolls with a speed of 4.0 m/s across a level table that is 1.0 m above the floor. Upon reaching the edge of the table, it
follows a parabolic path to the floor. How many meters along the floor is the landing spot from the table?
Answer: 1.81m
Explanation:
Given the following:
Horizontal speed = 4m/s
Height of table = 1m
Taking the vertical component of the motion:
Using:
S = ut + 0.5 at^2
Where, S = height of table, a = acceleration due to gravity (9.8m/s^2), t = time and u = Initial Velocity in vertical direction = 0
1 = 0(t) + 0.5(9.8)t^2
1 = 4.9t^2
t^2 = 1 / 4.9
t^2 = 0.204081
t = sqrt(0.204081)
t = 0.452s
For Horizontal :
Gravitational acceleration is absent, therefore distance can be calculated using:
Distance = Velocity × time
Distance = 4m/s × 0.452s
Distance = 1.808 m
Distance = 1.81m
HELP PLEASE!! A yellow ball with a mass of 2kg is rolling across the floor at 3m/s. A red ball with a mass of 3kg is rolling across the same floor at 3m/s. Which ball has greater kinetic energy, and why?
Answer: B. The red ball has greater kinetic energy, because it has a greater mass.
Explanation:
The factors influencing the kinetic energy of an object are its mass and its velocity. Both of the balls have the same velocity; however, the red ball has a greater mass. Therefore,
The red ball has greater kinetic energy, because it has a greater mass.
I hope this helps:)
On which of the following objects, all sitting on the ground together, does
Earth exert a greater gravitational pull than a pencil? Check all that apply.
A. A basketball
B. A toothpick
C. A truck
D. A piece of paper
E. Your hand
Explanation:
a toothpick
