# A small 5.50- rocket burns fuel that exerts a time-varying upward force on the rocket. This force obeys the equation . Measurements show that at , the force is 105.0 , and at the end of the first 2.40 , it is 177.0

98,233 results

**Physics**

A small 7.10kg rocket burns fuel that exerts a time-varying upward force on the rocket. This force obeys the equation F = A + Bt^2. Measurements show that at t = 0, the force is 121.0N, and at the end of the first 2.10s , it is 176.0N. Part A Find the net force on this rocket ...

**science**

a small weather rocket weighs 20.5 N. The rocket is carried up into the air by a balloon. The rocket is released from the balloon and fired. What is the acceleration of the rocket if an upward force of 25 N is applied? Net force = force up - force down. force down is its ...

**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 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?

**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**

Sorry for posting so many, but I just need to make sure I'm on the right track. Just need someone to check my working and answers. A rocket has a mass 3000kg. The fuel used in the rocket has an additonal mass of 500kg. At the launch, the rocket accelerates at 4m/s/s. Using 10m...

**physiccs**

a rocket that has consumed all of its fuel continues to move upward slowed mostly by the force of gravity. If the rocket's mass is 75.0 g and it takes 1.2 sec for the rocket to stop, what is the change in the rocket's momentum? what is the rockets stopping distance?

**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**

At time t=0, a 2150kg rocket in outer space fires an engine that exerts an increasing force on it in the +x-direction. This force obeys the equation Fx=At2, where 1.45s is time, and has a magnitude of 781.25N when t = 1.45s . Find the SI value of the constant A.

**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 1.8×104 kg rocket has a rocket motor that generates 2.8×105 N of thrust. What is the rocket's initial upward acceleration? At an altitude of 5000 m the rocket's acceleration has increased to 6.3 m/s2 . What mass of fuel has it burned?

**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 lift-off?

**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**

A 15.0-kg test rocket is fired vertically from Cape Canaveral. Its fuel gives it a kinetic energy of 1961 J by the time the rocket motor burns all the fuel. What additional height will the rocket rise? m - how do you organize this? how do the J's fit in?

**physics**

a toy rocket is fired upward with a net force of 50N. Because of this force it accelerates at 25m/s^2. What is the mass of the rocket?

**physic**

Consider a rocket in space that ejects burned fuel at a speed of 1.5 km/s with respect to the rocket. The rocket burns 9 % of its mass in 310 s (assume the burn rate is constant). (a) What is the speed of the rocket after a burn time of 155.0 s? (suppose that the rocket starts...

**Physics**

Consider a rocket in space that ejects burned fuel at a speed of vex= 2.0 km/s with respect to the rocket. The rocket burns 8 % of its mass in 300 s (assume the burn rate is constant). (a) What is the speed v of the rocket after a burn time of 150.0 s? (suppose that the rocket...

**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(elena)**

Consider a rocket in space that ejects burned fuel at a speed of vex= 1.5 km/s with respect to the rocket. The rocket burns 8 % of its mass in 280 s (assume the burn rate is constant). (a) What is the speed v of the rocket after a burn time of 140.0 s? (suppose that the rocket...

**physics-forces**

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 IMP PLS**

Consider a rocket in space that ejects burned fuel at a speed of v_ex= 2.0 km/s with respect to the rocket. The rocket burns 10 % of its mass in 290 s (assume the burn rate is constant). (a) What is the speed of the rocket after a burn time of 145.0 s? (suppose that the rocket...

**Classical Mechanics Physics**

Consider a rocket in space that ejects burned fuel at a speed of vex= 1.5 km/s with respect to the rocket. The rocket burns 6 % of its mass in 310 s (assume the burn rate is constant). (a) What is the speed v of the rocket after a burn time of 155.0 s? (suppose that the rocket...

**physics**

A stationary rocket is launched vertically upward. After 4s, the rocket's fuel is used up and it is 225.6 m above the ground. At this instant the velocity of the rocket is 112,8 m/s. Then the rocket undergoes free fall. Ignore the effect of the air friction.Assume that g does ...

**Physics**

I have to design a procedure which allows me to calculate the applied rocket thrust force of a stomp rocket. The only materials I am allowed are stop watches, rulers, measuring tape, protractors and the stomp rocket. Basically it all has to be done mathimatically. I so far ...

**Physics**

A 19 N thrust is exerted on a 0.4 kg rocket for a time interval of 8 s as it moves straight up. (Neglect all forces except this thrust and the force of gravity.) The rocket then continues to move upward as its speed reduces steadily to zero. (a) What is the maximum height that...

**Physics**

A 19 N thrust is exerted on a 0.4 kg rocket for a time interval of 8 s as it moves straight up. (Neglect all forces except this thrust and the force of gravity.) The rocket then continues to move upward as its speed reduces steadily to zero. (a) What is the maximum height that...

**Physics**

I have to design a procedure which will allow me to calculate the applied force(thrust) of a stomp rocket. We are allowed to use tools to find measurements. So far, I have calculated the height that the rocket reached (22.5) m using trig. (right angle triangle where one angle ...

**physicS IMP PLS**

Consider a rocket in space that ejects burned fuel at a speed of Vex = 1.5 km/s with respect to the rocket. The rocket burns 5% of its mass in 280 seconds. (a) What is the speed V of the rocket after a burn time of 140 seconds (in m/s)? (b) What is the instantaneous ...

**physics**

(ignore the other question i posted this is the right one) A rocket has a pre-ignition mass of 1100kg. On ignition it burns fuel at rate of 20kg s-1 producing a thrust of 10000N. How long after ignition of the fuel, will the rocket lift off? also explain how is it possible for...

**physics**

A 1680- kg rocket is launched with a velocity v0 = 55 m/s against a strong wind. The wind exerts a constant horizontal force Fwind = 15600 N on the rocket. At what launch angle will the rocket achieve its maximum range?

**physics**

During a lift off , the thrust a rocket produces must overcome the force of gravity in order to lift the rocket off the ground. If a rocket with a mass of 5kg produces a force of 180N, how fast will the rocket be travelling 3 seconds after ignition?

**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?

**NIC**

A model rocket is launched straight up from ground level with a speed of 34.2 m/s. Assuming that the only force acting on the rocket after launch is the force of gravity, a. How fast is the rocket going when it reaches a height of 22.5 m? (3 marks) b. How long does it take the...

**Physics**

The Spent Rocket Parts: During launches, rockets often discard parts. A certain rocket starts from rest on the launch pad and accelerates upward at a steady 3.3 m/s2. When it is 235 m above the launch pad, the rocket discards a used fuel canister by simply disconnecting it. ...

**physics**

The rate of burning of fuel in a rocket is 50 g/sec and comes out with a velocity 4X1000 sec. then find the force extended by fuel on the rocket.

**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.

**gr 11 physics**

as a rocket carrying a space probe acceleraes away from earth the fuel is being used up and the rocket's mass becomes less when the mass of a rocket(and its fuel) is M and the distance of the rocket from eart's centre is 1.5rE, the force of gravitational attraction between ...

**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**

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**

The solid fuel of a 300.kg rocket travelling at 1.64x104 km/h is ignited to correct the rocket trajectory in mid-flight to Mars. 10.00 kg of fuel is burnt in 15.00 s. If the exhaust velocity of the fuel, relative to the rocket, is 2.90x103 km/h, what is the acceleration of the...

**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 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**

A rocket burns 5kg per ejecting it as a gas with a velocity of 1600m/s relative to the rocket. How much force is exerted on the rocket. Also find the velocity exerted when its mass reduces to 1/200 of its initial mass.

**Physics**

A model rocket is launched vertically upward from the ground. After 4.3s, its fuel is completely burned. Assume uniform acceleration of 3.0 m/s2 while the fuel is burning. What is the velocity of the rocket at the instant that the fuel is completely burned? What's the rocket's...

**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**

Compute the initial upward acceleration of a rocket of mass 1.5 ✕ 104 kg if the initial upward force produced by its engine (the thrust) is 2.7 ✕ 105 N. Do not neglect the weight of the rocket. Pleas tell me the steps, I've tried getting the acceleration and ...

**physics Classical Mechanics**

Consider a rocket in space that ejects burned fuel at a speed of vex= 1.5 km/s with respect to the rocket. The rocket burns 8 % of its mass in 280 s (assume the burn rate is constant). (a) What is the speed v of the rocket after a burn time of 140.0 s? (suppose that 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 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**

Consider a rocket in space that ejects burned fuel at a speed of vex= 2.0 km/s with respect to the rocket. The rocket burns 10 % of its mass in 340 s (assume the burn rate is constant). (a) What is the speed v of the rocket after a burn time of 170.0 s? (suppose that 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 (Urgent)!!!!!!!!!!!!!!!!!!!!!!**

Consider a rocket in space that ejects burned fuel at a speed of vex= 1.5 km/s with respect to the rocket. The rocket burns 8 % of its mass in 280 s (assume the burn rate is constant). (a) What is the speed v of the rocket after a burn time of 140.0 s? (suppose that the rocket...

**Physics newton**

A rocket weighs 1 x10^7 N while on the surface of the earth. The ignition of its engines results in a lift off force of 1.5 X 10^7 N a) what is the mass of the rocket. b) what is its acceleration at lift -off c)How fast will it be moving if it acceleartion at this rates for 10...

**Physics**

You launch a model rocket up into the sky. Right after launch the rocket is accelerating upwards at 10~m/s^2. What is the magnitude of the net force in Newtons on the rocket if the rocket has a mass of 0.1 kg?

**physics**

You launch a model rocket up into the sky. Right after launch the rocket is accelerating upwards at 10 m/s2. What is the magnitude of the net force in Newtons on the rocket if the rocket has a mass of 0.1 kg?

**Physics**

You launch a model rocket up into the sky. Right after launch the rocket is accelerating upwards at 10~m/s^2. What is the magnitude of the net force in Newtons on the rocket if the rocket has a mass of 0.1 kg?

**physics**

You launch a model rocket up into the sky. Right after launch the rocket is accelerating upwards at 10 m/s2. What is the magnitude of the net force in Newtons on the rocket if the rocket has a mass of 0.1 kg?

**physics**

You launch a model rocket up into the sky. Right after launch the rocket is accelerating upwards at 10 m/s^2. What is the magnitude of the net force in Newtons on the rocket if the rocket has a mass of 0.1 kg?

**Physics**

You launch a model rocket up into the sky. Right after launch the rocket is accelerating upwards at 10~m/s^2. What is the magnitude of the net force in Newtons on the rocket if the rocket has a mass of 0.1 kg?

**Science**

You launch a model rocket up into the sky. Right after launch the rocket is accelerating upwards at 10 m/s2. What is the magnitude of the net force in Newtons on the rocket if the rocket has a mass of 0.1 kg?

**Physics**

The MAVEN spacecraft, a NASA mission that is studying the Martian atmosphere, launched from Cape Canaveral in November 2013 on an Atlas V rocket. The rocket burns about 280,000 kg of fuel over 4 minutes (you can assume dm/dt is constant over that interval) and ejects the fuel ...

**Math (calculus)**

Prof gave us this question to practice but I do not know how to solve it. If you know please provide step by step with the answer so I can understand it. Thank you very much :) Suppose a rocket is launched from the ground with 10 seconds worth of fuel. The rocket has an upward...

**Physics**

A rocket blasts off vertically from rest on the launch pad with an upward acceleration of 2.30 . At 10.0 after blastoff, the engines suddenly fail, which means that the force they produce instantly stops. How high above the launch pad will the rocket eventually go? Find the ...

**physics**

You launch a model rocket up into the sky. Right after launch the rocket is accelerating upwards at 10 m/s^2. What is the magnitude of the net force in Newtons on the rocket if the rocket has a mass of 0.1 kg? Please give your answer with solution .

**physics**

A fully loaded Saturn V rocket has a mass of 2.92*10^6. Its engines have a thrust of 3.34*10^7 N What is the unbalanced force of gravity on the rocket at blast off What is the unbalanced force on the rocket at blast off

**Physics**

A constant force of 100N , directed upward, is applied to a 5.0kg toy rocket by the rocket's engine. Find the rockets acceleration? I thought it'd be as simple as F=ma to be 20 m/s2 but I was wrong. What am I overlooking?

**physics**

Rockets A and B are fired straight upward from rest. Rocket A is launched first and accelerates at 11.2 m/s2. Rocket B is launched 2.10 s after Rocket A and B accelerates at 14.6 m/s2. Solve for the moment in time when the rockets are separated by 484 m. a) how long after ...

**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 free-fall). The rocket eventually stops rising and then falls back to the ground. (a) What is the highest point 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 rocket is fired straight up and accelerates upward at 24 m/s2 for 12 seconds. The rocket then runs out of fuel and coasts. Ignore any air resistance effects and use -9.8 m/s2 for the local acceleration due to gravity. a) What is the rocket’s maximum altitude? b) How long ...

**Physics**

Pam, wearing a rocket pack, stands on frictionless ice. She has a mass of 44 kg. The rocket supplies a constant force for 22.0 m, and Pam acquires a speed of 62.5 m/s. Assume that air resistance is negligible. (a) What is the magnitude of the force?

**Physics**

Imagine a fender bender between a large truck and a small car. During the impact, Choose one answer. a. the truck exerts a greater amount of force on the car than the car exerts on the truck b. the car exerts a greater amount of force on the truck than the truck exerts on the ...

**physics**

A draft horse exerts a horizontal force of 600 N dragging a log, on which the force of friction is 500 N. The force due to gravity on the log is 700 N and the ground exerts an upward force of 700 N on it. What is the net force acting on the log?

**physics**

The engines of a 1.20 x 10^5 N rocket exert an upward thrust of 2.00 x 10^5 N for 1.50 minutes upon lift off. What is the impulse exerted on the rocket? What is the velocity of the rocket at the end of the 1.50 minute period? physics - bobpursley, Thursday, February 3, 2011 at...

**Physics**

A model rocket is launched from rest with an upward acceleration of 6.30 m/s2 and, due to a strong wind, a horizontal acceleration of 1.50 m/s2. How far is the rocket from the launch pad 5.30 s later when the rocket engine runs out of fuel?

**Calculus**

The gravitational force, F, on a rocket at a distance, r, from the center of the earth is given by F=k/r^2 where k = 10^13 newton • km2. When the rocket is 10^4 km from the center of the earth, it is moving away at 0.2 km/sec. How fast is the gravitational force changing at ...

**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**

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 ...

**Hard Calculus**

The gravitational force, F, on a rocket at a distance, r, from the center of the earth is given by F=k/r^2 where k = 10^13 newton • km2. When the rocket is 10^4 km from the center of the earth, it is moving away at 0.2 km/sec. How fast is the gravitational force changing at ...

**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 model rocket is launched from rest with an upward acceleration of 5.50 m/s^2 and, due to a strong wind, a horizontal acceleration of 1.50m/s^2 . How far is the rocket from the launch pad 7.20 later when the rocket engine runs out of fuel?

**Physics**

Pam has a mass of 35.5 kg and she is at rest on smooth, level, frictionless ice. Pam straps on a rocket pack. The rocket supplies a constant force for 29.2 m and Pam acquires a speed of 64.1 m/s. What is the magnitude of the force?

**Physics**

A 360 g model rocket is on a cart that is rolling to the right at a speed of 2.5 m/s. The rocket engine, when it is fired, exerts an 8.5 N thrust on the rocket. Your goal is to have the rocket pass through a small horizontal hoop that is 20 m above the launch point. At what ...

**physics**

A rocket, initially at rest on the ground, accelerates straight upward with a constant acceleration of 34.3 . The rocket accelerates for a period of 8.00 before exhausting its fuel. The rocket continues its ascent until its motion is halted by gravity. The rocket then enters ...

**Physics**

A test rocket is launched vertically from ground level (y=0m), 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 97 m and acquired a velocity of 40 m/s. The rocket continues...

**physics please help**

A rocket, initially at rest on the ground, accelerates straight upward with a constant acceleration of 29.4 . The rocket accelerates for a period of 10.0 before exhausting its fuel. The rocket continues its ascent until its motion is halted by gravity. The rocket then enters ...

**Physics**

A rocker acceleratess up ar 5m/s/s for 10s and at which point the fuel is exhusted, and then the rocket continues upwards in free fall. a)How high does the rocket riseb)What total time does the rocket spend in the air? b) What total time does the rocket spend in the air? The ...

**Physics**

A model rocket is launched straight upward with an initial speed of 50 m/s. It accelerates with a constant upward acceleration of 2.00 m/s^2 until its engines stop at an altitude of 150 m. a) What is the max. height reached by the rocket? b) When does the rocket reach max. ...

**physics**

A rocket flies upward with a velocity of 1050 km/h and at an angle of 30 degrees to the vertical. If the rocket runs out of fuel determine: (i) The maximum additional altitude, h. (ii) The corresponding time. (iii) The horizontal distance at this time The gravitational ...

**physics**

A 1000kg rocket is moving forward at 10m/s in space. A 10,000N force is applied to the rocket for one second from behind. How fast is the rocket now traveling? a. 0m/s b. 10m/s c. 15m/s d. 20m/s

**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 ...

**physics**

a rocket is launched from atop a 105-foot cliff with an initial velocity of 156 ft/s.The height of the rocket above the ground at time or t is given by h=-16tsquared+156t+105. When will the rocket hit the ground after it is launched?

**physics**

A rocket moves straight upward, starting from rest with an acceleration of +25.5 m/s2. It runs out of fuel at the end of 4.26 s and continues to coast upward, reaching a maximum height before falling back to Earth. (a) Find the rocket's velocity and position at the end of 4.26...

**physics**

A rocket moves straight upward, starting from rest with an acceleration of +25.5 m/s2. It runs out of fuel at the end of 4.26 s and continues to coast upward, reaching a maximum height before falling back to Earth. (a) Find the rocket's velocity and position at the end of 4.26...

**Physics**

A rocket is fired vertically with an acceleration of 16m/s^2. After time T, the rocket's engine runs out of fuel and it begins to fall freely. The maximum height of the rocket is 940m, what is the minimum value of T?

**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**

I'm comparing the "g-force" of a rocket and a race car. My answer for the race car corresponds to the answer in the book but my answer for the rocket is off by 1. The book says I need to add 1 G because the rocket is going upward. So, instead of my answer of .87 G, the correct...

**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...