Fig. 2.1 shows a train
Fig. 2.1
The total mass of the train and its passengers is 750000kg. The train is travelling at a speed of 84m/s.
The driver applies the brakes and the train takes 80s to slow down to a speed of 42m/s.
(a) Calculate the impulse applied to the train as it slows down,
impulse =
[3]
(b) Calculate the average resultant force applied to the train as it slows down,
force =
(2)
Answer:
[tex]\mathrm{(a)\:}32,000,000\:\mathrm{Ns},\\\mathrm{(b)\:}390,000\:\mathrm{N}[/tex]
Explanation:
The impulse-momentum theorem states the impulse on an object is equal to the change in momentum of that object. Momentum is given by [tex]p=mv[/tex]. Since mass is constant, the train's change in momentum is:
[tex]\Delta p=m\Delta v=750,000\cdot42=31,500,000=\fbox{$32,000,000\:\mathrm{Ns}$}[/tex](two significant figures).
Impulse is also given as [tex]\Delta p = F\Delta t[/tex], where [tex]F[/tex] is the average force applied and [tex]\Delta t[/tex] is change in time. Since [tex]t[/tex] is given as [tex]80\mathrm{s}[/tex], we have the following equation:
[tex]F\Delta t=\Delta p\\\\F=\frac{\Delta p}{\Delta t},\\\\F=\frac{31,500,000}{80},\\\\F=393,750=\fbox{$390,000\:\mathrm{N}$}[/tex](two significant figures).
How is Heat Transfer different from Thermal Energy Transfer
Answer:
ExplaHeat can travel from one place to another in three ways: Conduction, Convection and Radiation. ... Thermal energy is transferred from hot places to cold places by convection. Convection occurs when warmer areas of a liquid or gas rise to cooler areas in the liquid or gas.nation:
What led astronomers to believe in the existence of dark matter?
A. the fact that space is black
B. the big bang theory
C. the apparent effects of the gravity of unseen matter on visible objects
D. the existence of black holes
Who was the most famous member of the Underground Railroad?
Answer:
Harriet Tubman
Explanation:
Answer:
Harriet Tubman
Explanation:
She was an abolitionist and fought for women's rights.
Harriet was also the first woman to lead a combat assault.
Four velcro-lined air-hockey disks collide with each other in a perfectly
inelastic collision. The first disk has a mass of 50.0 g and a velocity of
0.80 m/s to the west, the second disk has a mass of 60.0 g and a velocity of
2.50 m/s to the north, the third disk has a mass of 100.0 g and a velocity of
0.20 m/s to the east, and the fourth disk has a mass of 40.0 g and a
velocity of 0.50 m/s to the south. What is the final velocity of the disks
after the collision?
Answer:
The magnitude of the final velocity is approximately 0.526 m/s in approximately the direction of 8.746° East of South
Explanation:
The given collision parameters are;
The kind of collision experienced by the four velcro-lined air-hockey disk = Inelastic collision
The mass of the first disk, m₁ = 50.0 g
The velocity of the first disk, v₁ = 0.80 m/s West = -0.8·i
The mass of the second disk, m₂ = 60.0 g
The velocity of the second disk, v₂ = 2.50 m/s North = 2.5·j
The mass of the third disk, m₃ = 100.0 g
The velocity of the third disk, v₃ = 0.20 m/s East = 0.20·i
The mass of the fourth disk, m₄ = 40.0 g
The velocity of the fourth disk, v₄ = 0.50 m/s South = -0.50·j
Therefore, the total initial momentum of the four velcro-lined air-hockey disk, [tex]\Sigma P_{initial}[/tex] is given as follows;
[tex]\Sigma P_{initial}[/tex] = m₁·v₁ + m₂·v₂ + m₃·v₃ + m₄·v₄ = 50.0×(-0.80·i) + 60.0×(2.50·j) + 100 × (0.20·i) + 40.0 × (-0.50·j)
∴ [tex]\Sigma P_{initial}[/tex] = -40·i + 150·j + 20·i - 20·j = -20·i + 130·j
∴ [tex]\Sigma P_{initial}[/tex] = -20·i + 130·j
By the law of conservation of linear momentum, we have;
[tex]\Sigma P_{initial} = \Sigma P _{final}[/tex] = -20·i + 130·j
Therefore, given that the collision is perfectly inelastic, the disks move as one after the collision and the four masses are added to form one mass, "m", m = m₁ + m₂ + m₃ + m₄ = 50.0 + 60.0 + 100.0 + 40.0 = 250.0
∴ m = 250.0 g
Let, "v" represent the final velocity of the four disks moving as one after the collision
We have;
[tex]\Sigma P _{final}[/tex] = m × v = 250.0 × v = -20·i + 130·j
∴ v = -20·i/250 + 130·j/250 = -0.08·i + 0.52·j
The final velocity of the four disks after collision, v = -0.08·i + 0.52·j
The magnitude of the final velocity, [tex]\left | v \right |[/tex] = √((-0.08)² + (0.52)²) ≈ 0.526
[tex]\left | v \right |[/tex] ≈ 0.526 m/s
The direction of the final velocity, θ = arctan(0.52/(-0.08)) ≈ -81.254°
The direction of the final velocity, θ ≈ -81.254° which is 8.746° East of South
Hi!! Does anyone know the answer!! :D
Answer:
C. Contour Farming
A cell of e.M.F 1.5v and internal resistance 2.5ohm is connected in series with an ammeter of resistance 0.5ohm. Calculate the current in the circuit.
Given :
A cell of e.m.f 1.5 V and internal resistance 2.5 ohm is connected in series with an ammeter of resistance 0.5 ohm.
To Find :
The current in the circuit.
Solution :
We know, resistance of the ammeter is in series with the circuit.
So, total resistance is :
R = 2.5 + 0.5 ohm
R = 3 ohm
Also, e.m.f applied is 1.5 V .
Now, by ohm's law :
[tex]I = \dfrac{V}{R}\\\\I = \dfrac{1.5}{3}\\\\I = 0.5 \ A[/tex]
Therefore, the current in the circuit is 0.5 A.
The density of molten lava increases as the lava cools and hardens. Give other examples of natural change in density
Answer:
When the water is frozen it turns to ice and the density decreases.
Explanation:
Have A Wonderful Day !!
Putting the ball back into play by the offense is called a ____ ____
Answer:
Hand ball ?
Explanation:
can someone please help me it’s 15 points of my major grade..
a.
b.
c.
e.
f.
g.
character limit thing
I WANT TO PLAY UNDERTALE PLS HELP 100 PTS SINENCE
Answer:
Use IGG Games or get money.
Explanation:
Answer:
Go to Undertale.com and buy it
Explanation:
sorry i don't really know how to answer this
Which image illustrates the bouncing of a light wave off of a surface?
A
B
с
D
A. A
B. B
C. C
Answer:
The answer is A good luck :P
Answer:
A
Explanation:
The light Bounces off because it is reflecting off glass or anything else
Polar dissolves
A. nonpolar
B. polar
C. all molecules
D. none of the above
Polar substances are likely to dissolve in polar solvents.
Your answer is B.
How are CD's recorded?
Using digital technology
using analog technology
Answer:
its digital technology
How would I solve this? It's Newton's 2nd law
Answer:
5.65 m/s²
Explanation:
We'll begin by calculating the mass of PJ when in San Diego (i.e Earth). This can be obtained as follow:
Weight of PJ on Earth (Wₑ) = 545 N
Acceleration due to gravity (g) on Earth (gₑ) = 10 m/s²
Mass of PJ on Earth (mₑ) =.?
Wₑ = mₑ × gₑ
545 = mₑ × 10
Divide both side by 10
mₑ = 545 / 10
mₑ = 54.5 Kg
Thus, the mass of PJ on San Diego (i.e Earth) is 54.5 Kg
Finally, we shall determine the acceleration due to gravity of planet Koja. This can be obtained as follow:
Weight of PJ on Koja (Wₖ) = 308 N
Mass of PJ on Koja (mₖ) = mass of PJ on Earth (mₑ) because mass is constant irrespective of location.
Mass of PJ on Earth (mₑ) = 54.5 Kg
Mass of PJ on Koja (mₖ) = 54.5 Kg
Acceleration due to gravity of on Koja (gₖ) =?
Wₖ = mₖ × gₖ
308 = 54.5 × gₖ
Divide both side by 54.5
gₖ = 308 / 54.5
gₖ = 5.65 m/s²
Thus, the acceleration due to gravity on planet Koja is 5.65 m/s²
While playing hockey, player 1 is speeding down the rink, and doesn't see player 2 standing still on the ice. Player 1
collides with player 2. Explain what happens to the kinetic energy and motion of each player during the collisiort.
Answer:
There are two answers:
When player 1 collided with player 2, player 1's kinetic energy transferred to player 2.
Player 1 could slow down, stop , change direction, or fall, while player 2 would begin moving away from the collision point and possibly fall.
Explanation:
this is a voice recording of the text of a book that you listen rather than read.
The middle one please need done in 45min
Answer:
600 J
Explanation:
it's obviously btw so yeahhhh
I think this is physics?
A student wants to calculate the density of the two objects shown below:
A Metal Cube and a Small Statue.
Describe the methods that the student should use to calculate the densities of the two objects.
ASAP please this piece of work is already late XD
Answer:
Okay
Explanation:
First we should quickly remind ourselves of the equation for density:density= mass/ volumeTo calculate the density we need a method of measuring the mass of each object and another method for measuring the volume of each object. To measure the mass in both cases we can simply use a measuring balance. To measure the volume we will need to use 2 separate methods. For the cube we can simply measure the length, height and depth with a ruler, multiply our measurements and we obtain the volume. The statue is a little more tricky because it has an irregular shape so we can't use the ruler anymore. Instead we should use graduated tank/trough of water. First of all measure the amount of water in the tank before putting in the statue. Then submerge the statue in the water and take another measurement of the volume of water in the tank. The statue will displace the water in the tank giving a higher value. We finally subtract the initial volume from the final volume and we should obtain the volume of the statue.We now have all the measurements necessary to calculate the density of both objects!
what is a recovery heart rate?
Answer:Recovery heart rate is simply your pulse rate after exercise. Some fitness specialists refer to it as the post-exercise heart rate. The pulse number is used for different reasons in different settings.
Explanation:
Answer:
Heart rate is the speed of the heartbeat measured by the number of contractions of the heart per minute.
Explanation:
In water, sound travels 1500 m/s. A whale sings at a frequency of 17 Hz. What will be the length of the sound wave?
Answer:
A 20 Hz sound wave is 75 m long in the water (1500/20 = 75) whereas a 20 Hz sound wave in air is only 17 m long (340/20 = 17) in air. As we descend below the surface of the sea, the speed of sound decreases with decreasing temperature.
my friend wore a smart watch to bed,when he woke up in the morning it showed 300 steps taken how did this happen?
Answer:
Your tracker will detect your arm movement and will interpret it as steps so this is what it likely happening. Something similar happens while driving, if you go through a bumpy road or your car has a stiff suspension then this can cause the tracker to detect movement and count it as steps. Usually while driving and if you notice some vibration on your car or steering wheel you can try having your tracker a little bit more tight around your wrist and this will help decrease the amount of steps detected.
Explanation:
(Via AlvaroFitbit)
Which energy source contributes least to global warming?
A. Coal
B. Natural gas
C. Solar
D. Petroleum
Solar energy source contributes least to global warming. Hence option C is correct.
What is renewable and non renewable energy sources ?Renewable energy is a energy from a source that is not exhausted or depleted when used. Solar energy or wind energy are examples of the renewable energy source. as wind and solar power is abundantly present everywhere in the environment, it can not be exhausted after its over use.
Non-renewable energy comes from sources that will be exhausted or will not be replenished after its use. Fossil fuels: coal, petroleum, and natural gas are the examples of the non renewable energy sources . Coal is the main element in fossil fuels.
Solar energy is abundantly available in the entire solar system. It is renewable energy source, it has no bad effect on the environment and global warming.
Hence option C is correct.
To know more about solar energy :
https://brainly.com/question/9704099
#SPJ7.
Gamma radiation is composed of neutrons and protons.
A. True
B. False
Answer:
false
Explanation:
Answer:
The answer is B false
Explanation:
Gamma radiation is not composed of both neutrons and protons.
What is radiation? Explain in your own words.
Answer:
An energy source in which we use to power most powerplants and reactors.
Explanation:
A car with a mass of 1710 kg kg starts from rest and accelerates to a speed of 13.8 m/s in 13.5 s. Assume that the force of resistance remains constant at 367.1 N during this time.
What is the average power developed by the car’s engine?
Answer in units of W
Answer:
Average Power = 14599.24 W
Explanation:
We know that :
[tex]power = \frac{work \: done}{time} [/tex]
[tex]work \: done \: = force \times displacement \: \cos( \alpha ) [/tex]
Acceleration of car (a) = v - u / t
= 13. 8 - 0 / 13.5
= 1.02 m / sec ^2
Displacement (s) = v^2 / 2a
= 13.8 * 13.8 / 2.04
= 93.35 m
Now,
Resultant force = F (Car) - F (Resistance) = m * a
Force (Car) = m * a + Force (Resistance)
Force (Car) = 1744.2 + 367.1 = 2111.3 N
Work done by Car = Force (Car) * Displacement
= 2111.3 * 93.35 * Cos 0°
= 197089.85 J
Average Power = Work Done / time
= 197089.85 J / 13.5 sec
= 14599.24 W
what 5+1234567890987654345632675432
If the boy travelled 2 meters to the right and 4 meters to the left what is the total distance that he travelled?
4 m
-4 m
6 m
2 m
Answer:
6m
Explanation:
2+4=6
Metals are good conductors of heat because .
Answer:
They have the highest melting point so that mean that the temperature and the are a conductive to electricity.
Explanation:
An inclined plane is used to lift a box into a moving truck. The ramp is 6m long and 1.5m
from the ground. What is the mechanical advantage of the inclined plane?
Given :
An inclined plane is used to lift a box into a moving truck. The ramp is 6 m long and 1.5 m.
To Find :
The mechanical advantage of the inclined plane.
Solution :
Mechanical advantage, M.A of an inclined plane is given by :
[tex]M.A = \dfrac{\text{Length of slope}}{\text{Height of plane}}[/tex]
Putting given values in above equation, we get :
[tex]M.A = \dfrac{6 \ m}{1.5 \ m}\\\\M.A = 4[/tex]
Therefore, the mechanical advantage of the inclined plane is 4.