A rocket engine on a spacecraft of total mass 10,000kg ejected 1.4kg of hot gases every second at an average discontinuous speed of 240ms1. 1 What was the force on the spacecraft?
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physics
A rocket engine on a spacecraft of total mass 10,000kg ejected 1.4kg of hot gases every second at an average discontinuous speed of 240ms1. 1 What was the force on the spacecraft? 2 What was the acceleration of the spacecraft? 3If the engines were used for 30's, what was ... 
physics
Model rocket engines are sized by thrust, thrust duration, and total impulse, among other characteristics. A size C5 model rocket engine has an average thrust of 5.26 N, a fuel mass of 12.7 g, and an initial mass of 25.5 g. The duration of its burn is 1.90 s. (a) What is the ... 
physics
A 9800 kg rocket is travelling east along a horizontal fricitonless rail at a velocity of 11 m/s. The rocket is then accelerated uniformly to avelocity of 22 m/s in a time of 0.75 s by the expulsion of hot gases. What is the average force with which the gases are expelled by ... 
Physics
The Apollo spacecrafts were launched toward the moon using the Saturn rocket, the most powerful rocket available. Each rocket had five engines producing a total of 3.34 x 10 to the 7thX of force to launch the 2.77 x 10 to the 6 kg spacecraft toward the moon. (a) I need to find... 
physics
It is possible for the velocity of a rocket to be greater than the exhaust velocity of the gases it ejects. When that is the case, the gas velocity and momentum are in the same direction as the rocket's. How does the rocket still obtain thrust by ejecting the gases? Before the... 
PHYSICS answer check
A group of 4 rail cars with a total mass of 50,000kg moves at 3m/s at a stationary locomotives that has a mass of 10,000kg. What is the speed of the whole train after the cars connect with the locomotive? F=ma 50,000kg*3m/s= 150,000kg m/s 150,000kg m/s divided by 60,000kg a= 2... 
PHYSICS
what work must a diesel engine in an 18,000kg truck do to increase its speed from 30.m/s to 40 m/s in 5.0s? what average force did the engine exert? what power was needed (in horsepower) 
Physics
A rocket of mass 1.0x10^3kg is being fired to a height of 5.0 x 10^3 m. The rocket engine shuts off when the rocket reaches a height of 1.0x10^3m, and the rocket coasts up to 5.0 x 10^3 m. A) What velocity must the rocket have at the 1.0x10^3 m point to enable it to reach 5.0 ... 
physics
A 7710kg rocket is set for vertical firing from the earth's surface. If the exhaust speed is 1350 m/s, how much gas must be ejected each second in order for the thrust to be equal to the weight of the rocket? How much gas must be ejected each second to give the rocket an ... 
Physics
A rocket was launched and it now has an acceleration of 3m pers second squared upwards.the mass of the rocket is 5000kg.calculate the net force acting on the rocket and the upthrust exerted by the exhaust gases on the rocket. 
physics
i need help figuring out what formaula to use for finding the final velocity of a rocket. Model rocket engines are sized by thrust, thrust duration, and total impulse, among other characteristics. A size C5 model rocket engine has an average thrust of 5.26 N, a fuel mass of 12... 
Physics
A typical model rocket engine exerts an average force of 5 N on its exhaust gas. How much average thrust force does the gas exert on the engine and rocket? 
physics
For a safe reentry into the Earth's atmosphere the pilots of a space capsule must reduce their speed from 2.6 104 m/s to 1.0 104 m/s. The rocket engine produces a backward force on the capsule of 1.7 105 N. The mass of the capsule is 3800 kg. For how long must they fire their... 
space
A space capsule needs to have its speed inceased slightly to set it on course.A spaceship moves up slowly to the capsule, and makes contact with it.The spaceship's rocket engine is fired for 10s. The gases exert a forward force of 12000n on the spaceship during the time the ... 
physics
Identify the force that propels a rocket. 1)The rocket is propelled by the reaction force of the exhaust gasses bouncing off the air molecules outside the rocket. 2)The rocket is propelled because the action force of the rocket on the exhaust gases is greater than the reaction... 
physics
Identify the force that propels a rocket. 1)The rocket is propelled by the reaction force of the exhaust gasses bouncing off the air molecules outside the rocket. 2)The rocket is propelled because the action force of the rocket on the exhaust gases is greater than the reaction... 
physics
A rocket engine consumes 450 kg of fuel per minute. If the exhaust speed of the ejected fuel is 5.2 km/s, what is the thrust of the rocket? 
Physics
A rocket has put your spacecraft in a circular orbit around Earth at an altitude of 350 km. Calculate the force due to gravitational between the Earth and the spacecraft in N if the mass of the spacecraft is 2450 kg. 
physics
A Titan IV rocket has put your spacecraft in a circular orbit around Earth at an altitude of 230 km. Calculate the force due to gravitational attraction between the Earth and the spacecraft in N if the mass of the spacecraft is 2300 kg. 
Physics
The mass of a spacecraft is about 480 kg. An engine designed to increase the speed of the spacecraft while in outer space provides 0.09 N thrust at maximum power. By how much does the engine cause the craft's speed to change in 1 week of running at maximum power? Describe any ... 
Physics
A rocket whish is in deep space and initially at rest relative to an inertial reference frame, has a mass of 2.55 X 10^5 kg of which 1.81 X10^5 kg is fuel. The rocket engine is then fired for 250 s during which feul is consumed at the rate of 480 kg/s. The speed of the exhaust... 
physics
A spacecraft of mass is first brought into an orbit around the earth. The earth (together with the spacecraft) orbits the sun in a near circular orbit with radius ( is the mean distance between the earth and the sun; it is about 150 million km). (a) What is the speed (in m/s) ... 
physics
A rocket with mass of 60,000 kg is placed on a launching platform verticlly. its engine is started and the rocket gives out gas at rate of 50kgs^1 with a speed of 5000ms^1 a) calculate the up trust force caused by the gas. b) can the rocket be launched at this moment? 
PHYSICS
A catapult launches a rocket at an angle of 56.9° above the horizontal with an initial speed of 100 m/s. The rocket engine immediately starts a burn, and for 3.25 s the rocket moves along its initial line of motion with an acceleration of 28.1 m/s2. Then its engine fails, and... 
Physics
A small rocket weighs 14.7 newtons. The rocket is fired from a high platform but it's engine fails to burn properly. The rocket gains total upward force if only 10.2 newtons. At what rate and in what direction is the rocket accelerated? 
physics
A rocket of total mass 2580 kg is traveling in outer space with a velocity of 111 m/s. To alter its course by 32.0 degrees, its rockets can be fired briefly in a direction perpendicular to its original motion. If the rocket gases are expelled at a speed of 1560 m/s, how much ... 
physics
The hot reservoir for a Carnot engine has a temperature of 926 K, while the cold reservoir has a temperature of 441 K. The heat input for this engine is 3730 J. The 441K reservoir also serves as the hot reservoir for a second Carnot engine. This second engine uses the ... 
physics
A catapult launches a rocket at an angle of 47.5° above the horizontal with an initial speed of 109 m/s. The rocket engine immediately starts a burn, and for 2.49 s the rocket moves along its initial line of motion with an acceleration of 30 m/s2. Then its engine fails, and ... 
chemistry
A spark plug fires before the gases in a cylinder are fully compressed. How will the engine be affected? A. The engine will get better gas mileage as less fuel is burned during each cycle. B. There will be fewer pollutants as the fuel has more time to burn. C. The gases will ... 
chemistry
A spark plug fires before the gases in a cylinder are fully compressed. How will the engine be affected? A. The engine will get better gas mileage as less fuel is burned during each cycle. B. There will be fewer pollutants as the fuel has more time to burn. C. The gases will ... 
chemistry
A spark plug fires before the gases in a cylinder are fully compressed. How will the engine be affected? A. The engine will get better gas mileage as less fuel is burned during each cycle. B. There will be fewer pollutants as the fuel has more time to burn. C. The gases will ... 
Mpindweni s.s.s science
A rocket of mass 5000kg is launched vertically upwards into the sky at an acceleration of 2om/s. The magnitude of the force due to gravity on the rocket is 49000 N calculate the magnitude and diretion of the force of the rocket's engine. 
Physics
A rocket is fired vertically with an upward acceleration of 30 m/s2. After 20 s, the engine shuts off and the rocket then continues rising (while in freefall). The rocket eventually stops rising and then falls back to the ground. (a) What is the highest point the rocket ... 
Physics
A typical model rocket has a mass of 50 g. Similarly, a typical "class C" model rocket engine can produce a total impulse of 10 Newtonseconds. We usually launch model rockets vertically, but if I instead launched this rocket horizontally, how fast would it be going in m/s ... 
Chemistry
A spark plug fires before the gases in a cylinder are fully compressed. How will the engine be affected? A. The engine will get better gas mileage as less fuel is burned during each cycle. B. There will be fewer pollutants as the fuel has more time to burn. C. The gases will ... 
Physics
A rocket with initial mass of 7.50×103 kg is fired in the vertical direction. Its exhaust gases are ejected at the rate of 4.50×101 kg/s with a relative velocity of 2.200×103 m/s. What is the initial acceleration of the rocket? What is the acceleration after 20 s have elapsed? 
Physics
The mass of a rocket car plus fuel is 2,000kg. The rocket car starts from rest. The engine expels fuel(in the form of exhaust) over a period of 8 seconds. The exhaust has a velocity of 1,000m/s due west, and the velocity of the rocket car after 8 seconds is 90m/s due east. How... 
Physics
The mass of a rocket car plus fuel is 2,000kg. The rocket car starts from rest. The engine expels fuel(in the form of exhaust) over a period of 8 seconds. The exhaust has a velocity of 1,000m/s due west, and the velocity of the rocket car after 8 seconds is 90m/s due east. How... 
Physics
Energy Budget for a Rocket in Free Space: Recall the analysis of the rocket engine in Project I, Flight of the Rocket. Although the momentum of the rocket and its exhaust is conserved (constant), their energy is not; energy must be supplied by the combustion of fuel. WARNING: ... 
Physics
Energy Budget for a Rocket in Free Space: Recall the analysis of the rocket engine in Project I, Flight of the Rocket. Although the momentum of the rocket and its exhaust is conserved (constant), their energy is not; energy must be supplied by the combustion of fuel. WARNING: ... 
Physics
A rocket with a mass of 345 kg is launched vertically. the engine produces a thrust of 17000 N. Neglect air resistance. a. How would I determine the weight of the rocket? b. What is the net force being applied to the rocket? 
Physics
A spacecraft of mass 2000kg, moves at a constant speed of 7800m.s in space. the main engine switched on for 10s during which time the exhaust gases travels at 10 000m.s. As a result of this, the craft travels at 8000m.s after 10s. Calculate the mass of the exhaust gas. 
Physics
A rocket expels gases at a rate of 1.30 x 10^3 kg/s with a speed of 3.00 x 10^4 m/s. What is the force exerted on the rocket? 
physics
if a rocket engine delivers a constant thrust, does it deliver more power as the rocket speeds up force = mass*(acceleration) if the rocket accelerates, the force will increase wow,uh constant thrust means it is delivering constant power. the kenetic potential of the rocket ... 
physics  linear momentum with rockets
A rocket of total mass 3180 kg is traveling in outer space with a velocity of 115 m/s. To alter its course by 35.0 degrees, its rockets can be fired briefly in a direction perpendicular to its original motion. If the rocket gases are expelled at a speed of 1750 m/s, how much ... 
physicsforces
1. a fully loaded rocket has a mass of 2.92x10^6kg. It's engines has a thrust of 3.34x10^7N a)what is the downward force of gravity of the rocket at blast off? b)what is the unbalanced force on the rocket at blast off? c)what is the accleration of the rocket as it leaves the ... 
Physics
A toy rocket is launched upwards from rest. The rocket engine will cause the rocket to accelerate at 25 m/s^2 for 3.0 seconds. a) How fast is the rocket moving aft the end of the 3 seconds? b) What is the maximum height reached by the rocket? c) What is the total time the ... 
Physical
A toy rocket is launched vertically from ground level (y = 0 m), at time t = 0.0 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 73 m and acquired a velocity of The rocket continues to ... 
Physics (Energy and Momentum)
A 4400 kg rocket is set for vertical firing. If the exhaust speed is 1500 m/s, at what rate (in kilograms/second) must the gas be ejected to supply the thrust needed to give the rocket an initial upward acceleration of 23.0 m/s^2? Not sure where to start. 
Physics
a spacesatellite mass of 600kg fires a rocket engine for 2 seconds expelling 40kg of exhaust gases at 350m/s. By how much will the speed of the capsule change? You may consider the initial relative velocities to be zero, but would it matter? 
physics
A small weather rocket weighs 14.7 N. The rocket is carried up by a balloon. The rocket is released from the balloon and fired, and its engine exerts an upward force of 10.2 N on the rocket. What is the acceleration of the rocket? 
physics
A 425 g model rocket is accelerated upward at 86 m/s2 by its engine. What is the value of the force exerted by the engine on the rocket? 
Physics
A 70.0kg astronaut pushes to the left on a spacecraft with a force in "gravityfree" space. The spacecraft has a total mass of 1.0 × 104 kg. During the push, the astronaut accelerates to the right with an acceleration of 0.36 m/s2. Determine the magnitude of the ... 
Science
In a rocket, fuel burns at the rate of 1kg/s. This fuel is Ejected from the rocket with a velocity of 60km/s. What force will be exerted on the rocket? 
PHYSICS
Model rockets are lightweight rockets powered by very small engines. A typical model rocket has a mass of 5g.Similarly, a typical "class C" model rocket engine can produce a total impulse of 10 Newtonseconds. We usually launch model rockets vertically, but if I instead ... 
physics
You have designed a rocket to be used to sample the local atmosphere for pollution. It is fired vertically with a constant upward acceleration of 19 m/s2. After 23 s, the engine shuts off and the rocket continues rising (in freefall) for a while. (Neglect any effects due to ... 
motion,physics
Model rockets are lightweight rockets powered by very small engines. A typical model rocket has a mass of 5g.Similarly, a typical "class C" model rocket engine can produce a total impulse of 10 Newtonseconds. We usually launch model rockets vertically, but if I instead ... 
science
Couple of questions. Why does the earth keep moving? The engine of a rocket applies a continual force to push the rocket along. When the engine stops what will happen? I think the rocket will stop acceleration You need to be aware of the concept of inertia. Inertia is the ... 
physics
.10 kilogram rocket designed to deliver an impulse of 6 newtons seconds. If the rocket engine burns .75 seconds, what average force does it produce. 
Physics
A 10.2 kg weather rocket generates a thrust of 200N. The rocket, pointing upward, is clamped to the top of a vertical spring. The bottom of the spring, whose spring constant is 500N/m, is anchored to the ground. a) Initially before the engine is ignited, the rocket sits at ... 
Science
A rocket with mass 20000kg is launched straight upwards. the rocket experience an average drag force ( air resistance ) of 15000 N. What thrust force will be necessary for the rocket to maintain an acceleration of 4.5m/s square upwards? 
physics
A new SpaceX rocket is being tested and launches from the ground. The first stage rocket engine provides constant upward acceleration during the burn phase. After the first stage engine burns out, the rocket has risen to 105.0 m and acquired an upward velocity of The second ... 
Physics
An ice sled powered by a rocket engine starts from rest on a large frozen lake and accelerates at 15.0 m/s 2 . At t1 the rocket engine is shut down and the sled moves with constant velocity v for another t2 s. The total distance traveled by the sled is 5.60 × 10 3 m and the ... 
Physics
A model rocket builder has constructed a rocket of total mass of 1.0kg. The rocket must achieve a speed of 300m/s 5seconds after vertically leaving the launch pad. A) What acceleration and net force is required? B) What thrust must the motor have to achieve this? Thank you! 
Physics
an ice sled powered by a rocket engine starts from rest on a large frozen lake and accelerates at +13m/s^2. At t1, the rocket engine is shut down and the sled moves with constant velocity v until t2. The total distance traveled by the sled is 5.30*10^3 m and the total time is ... 
Physics
A model rocket is launched at 62 degrees above the horizontal with an initial speed of 28m/s. the rocket travels for 4.5s along its initial line of motion with a constant acceleration of 13 m/s^2. At this time, the engine of the rocket stops and the rocket proceeds to move as ... 
Physics
1.The mass of a string is , and it is stretched so that the tension in it is 180 N. A transverse wave traveling on this string has a frequency of 260 Hz and a wavelength of 0.60 m. What is the length of the string? 2.A rocket engine emits of sound energy every second. The ... 
physics
A small weather rocket weighs 15.5 N. The rocket is carried up by the balloon. The rocket is released from the balloon and fired, but its engine exerts an upward force of 11.0 N. What is the acceleration of the rocket? 
physics
A test rocket is launched vertically from ground level (y = 0 m), at time t = 0.0 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 49 m and acquired a velocity of What is the maximum ... 
Physics
1.The mass of a string is , and it is stretched so that the tension in it is 180 N. A transverse wave traveling on this string has a frequency of 260 Hz and a wavelength of 0.60 m. What is the length of the string? 2.A rocket engine emits of sound energy every second. The ... 
physics
Help please ! been stuck on this for hours. A model rocket blasts off and moves upward with an acceleration of 13m/s^2 until it reaches a height of 25m , at which point its engine shuts off and it continues its flight in free fall. 1) What is the maximum height attained by the... 
physics
Pam has a mass of 33.0 kg and she is at rest on smooth, level, frictionless ice. Pam straps on a rocket pack. The rocket supplies a constant force for 15.0 m and Pam acquires a speed of 60.0 m/s. (a) What is the magnitude of the force? 1 N (b) What is Pam's final kinetic ... 
Physics
a mass, m = 2.1 kg, is ejected horizontally from a compressed coil with a force constant, k = 5.2 N/m and compression, x = 25 cm, onto a rough ramp that is 1.5 cm long with one end raised to a height, h= 120 cm. the speed at the bottom of the rough ramp is v=+3.037 m/s. the ... 
Physics
A 6100 kg rocket is set for vertical firing from the ground. If the exhaust speed is 1200 m/s how much gas must be ejected each second if the thrust a) is to equal the magnitude of the gravitaiotnal force on the rocker and b) is to give the rocket an inital upward acceleration... 
physics
A 11.6 kg weather rocket generates a thrust of 215.0 N. The rocket, pointing upward, is clamped to the top of a vertical spring. The bottom of the spring, whose spring constant is 399.0 N/m, is anchored to the ground. Initially, before the engine is ignited, the rocket sits at... 
physics
An engine of mass 5000 kg pulls a train of ten trucks each of mass 2000 kg along a horizontal track. Assume that the frictional forces to be 5000 N and that the engine exerts a force of 50 000 N on the rails. If the trucks are numbered from 1 to 10 starting with the one next ... 
physics
You have designed a rocket to be used to sample the local atmosphere for pollution. It is fired vertically with a constant upward acceleration of 17 m/s2. After 20 s, the engine shuts off and the rocket continues rising (in freefall) for a while. (Neglect any effects due to ... 
Physics Help
A constant force of 100N , directed upward, is applied to a 5.0kg toy rocket by the rocket's engine. What is the rocket's acceleration? I used the equation a= F/m to get 20 m/s2 but it was wrong and I don't know where to go from here still? 
physics 11
The engine of a train has a mass of 5.0 x 10^4kg. It can accelaerate six railway cars having a total mass of 3.0 x 10^5 at 0.40 m/s squared [fwd]. What acceleration can it give four railway cars having a total mass of 2.0 x 10^5kg? Ignore friction 
Physics
A model rocket has a mass of 0.435 kg. It is mounted vertically and launches directly up with a thrust force of 13.1 N. a) What is the weight of the rocket? b) Determine the net force on the rocket as it is launched. c) What is the acceleration of the rocket at liftoff? 
physics
A model rocket is propelled upward by a cylinder of compressed water. The cylinder emits water at a rate of 0.050 kg/second with an exit speed of 80.0 m/s. Initially, the rocket has a mass of 0.15 kg, including the water cylinder. What is the rocket's initial upward ... 
physics
A model rocket is propelled upward by a cylinder of compressed water. The cylinder emits water at a rate of 0.050 kg/second with an exit speed of 80.0 m/s. Initially, the rocket has a mass of 0.15 kg, including the water cylinder. What is the rocket's initial upward ... 
physics
An ice sled powered by a rocket engine starts from rest on a large frozen lake and accelerates at +40 ft/s2. After some time t1, the rocket engine is shut down and the sled moves with constant velocity v for a time t2. If the total distance traveled by the sled is 17 500 ft ... 
chemistry
can you tell me what i did wrong on this problem Rigid rods of negligible mass lying along the y axis connect three particles. The system rotates about the x axis with an angular speed of 3.30 rad/s. 4kg,y=3.00m 2kg,y=2.00m 3kg,y=4.00m a)Find the total rotational kinetic ... 
PHYSICS
A model rocket is constructed with a motor that can provide a total impulse of 25.5 N · s. The mass of the rocket is 0.213 kg. What is the speed that this rocket achieves when launched from rest? Neglect the effects of gravity and air resistance. 
physics
A model rocket is constructed with a motor that can provide a total impulse of 25.5 N · s. The mass of the rocket is 0.213 kg. What is the speed that this rocket achieves when launched from rest? Neglect the effects of gravity and air resistance. 
physics
A 1000kg space probe is motionless in space. To start moving, its main engine is fired for 5 seconds during which time it ejects exhaust gases at 5000 m/s. At the end of this process it is moving at 20 m/s. The approx. mass of the ejected gas is?? 
physics(check my answer)
can you tell me what i did wrong on this problem Rigid rods of negligible mass lying along the y axis connect three particles. The system rotates about the x axis with an angular speed of 3.30 rad/s. 4kg,y=3.00m 2kg,y=2.00m 3kg,y=4.00m a)Find the total rotational kinetic ... 
Physics
A jet aircraft is traveling at 180 m/s in horizontal flight. The engine takes in air at a rate of 77.0 kg/s and burns fuel at a rate of 3.15 kg/s. The exhaust gases are ejected at 595 m/s relative to the speed of the aircraft. Find the thrust of the jet engine. (Take the ... 
physics
a rocket blasts off and moves up with an acceleration of 12 m/s2 until it reaches 30 m then the engine shuts down and the rocket continues in free fall. What is the max hieght of the rocket and what is the total duration of the rockets flight? 
physics
The engine of a toy rocket supplies an average acceleration of 38.0 m/s/s to the rocket for an interval of 0.80 s. A.)If the toy roocket is launched vertically, how high does it rise in this interval? B.) How fast is the rocket moving at the end of 0.80 s? C.) What altitude ... 
phyicis
Homer Hickham and his buddies launched model rockets in the late 1950's when the US was trying to get a rocket into space. If homer launches a rocket from rest and its engine delivers a constance acceleration of 8.2 m/s^2 for 5.0seconds after which the fuel is used up by the ... 
Physics
A new SpaceX rocket is being tested and launches from the ground. The first stage rocket engine provides constant upward acceleration during the burn phase. After the first stage engine burns out, the rocket has risen to 105.0 m and acquired an upward velocity of 50.0 m/s. The... 
Physics
A model rocket launches with an initial velocity of 6 m/s, at an angle of 90 degrees (with respect to the horizon). The rocket's engine provides an acceleration of 2.2 m/s2, acting in the same direction as the initial velocity. After 20 seconds, the rocket engine cuts out. ... 
physic
A sounding rocket, launched vertically upward with an initial speed of 79.0 m/s, accelerates away from the launch pad at 5.70 m/s2. The rocket exhausts its fuel, and its engine shuts down at an altitude of 1.15 km, after which it moves freely under the influence of gravity. a... 
physics
An ice sled powered by a rocket engine starts from rest on a large frozen lake and accelerates at +13.0 m/s^2. At t(subscript 1), the rocket engine is shut down and the sled moves with a constant velocity v until t(subscript 2). The total distance traveled by the sled is 5.30 ... 
Physics
A power boat of mass 475 kg is cruising at a constant speed of 8.9 m/s. The propeller provides a drive force of 770 N. The driver of the boat shuts off the engine, and the boat coasts to a halt. Assume  contrary to fact  that the resistive force due to the water is ... 
physics
1.The mass of a string is , and it is stretched so that the tension in it is 180 N. A transverse wave traveling on this string has a frequency of 260 Hz and a wavelength of 0.60 m. What is the length of the string? 2.A rocket engine emits of sound energy every second. The ... 
Physics
An engine is used to pull a train of two cars out of a mine. The floor slopes upward at an angle of 24o. Each car has a mass of 0.8x104 Kg and normally travels without friction on the tracks. The engine can exert a maximum force of 1.4x105 N on car A. If the engineer again ... 
college physics
a railway freightbcar whose mass is 15 000kg & speed is 2.4m/s runs into a stationary freight car whose mass is 25 000kg. the 2 cars couple & roll off the track. what is the speed if the 2 cars as tey move together down the track? and how much kinetic energy is lost in the ...