# How fast does the rocket leave the ramp?

• pauln
In summary, the problem involves a 1200 kg rocket car on a 100 m ramp with a 10 degree incline. The rocket is turned on and exerts a force of 8300 N for 5.7 seconds before shutting off. Using the equation F=ma, the net force can be calculated by considering the forces of gravity and the rocket. The acceleration can then be found and used to solve for the speed at which the rocket car leaves the ramp. When the rocket shuts off, the force of gravity is the only force acting on the car, allowing for the calculation of its deceleration. Using this deceleration, the distance traveled by the car can be found and used to determine its final speed.
pauln

## Homework Statement

A 1200 kg rocket car is placed at the bottom of a 100 metre long ramp inclined at 10 degrees. The rocket is turned on and it exerts a force of 8300 N for 5.7 seconds, and then it shuts down. Find the speed with which the rocket car leaves the ramp (assume frictionless)

## Homework Equations

http://img98.imageshack.us/img98/9425/54fl1.png

## The Attempt at a Solution

i missed a class involving kinematics and dynamics together so I am not entirely sure how to solve it

Last edited by a moderator:
i missed a class involving kinematics and dynamics together so I am not entirely sure how to solve it

So you DO understand kinematics, it's the dynamics with Newton's laws?

So here you have a force being exerted of 8300 Newtons. Your equation there, which was effectively the most important equation in physics from about 1666 to the late 1800s(damn you Maxwell)says the NET force is equal to the mass times the acceleration

Now this rocket car has two forces acting on it. One is the force of gravity, acting down the ramp, can you find that? It's not JUST mg, it's the component of mg acting down the ramp

The second force is the rocket, which is just 8300 Newtons, neato

So then Fgravity+Frocket=Fnet (Frocket is obviously positive, Fgravity, acting in the opposite direction, will be negative)

Once you find Fnet, you know that and mass, so you can find acceleration. So then you'll have a constant acceleration and you'll know for how long, and you can solve that type of problem I think. THEN the rocket cuts off, and you can find the speed when it cuts off and the distance it has traveled to that point. I'm guessing it'll still be less than a 100 m so you'll have to then look at JUST the force of gravity(which will be the same from earlier)and find that acceleration(which will be negative this time)

Then you'll have acceleration again, and you'll know how much farther to the end of the ramp so you'll have distance, and you'll know the initial speed, so another of those

Don't be intimidated, it's just two problems that are like the ones you've done a million times before, the only difference is you have to use F=ma to find your own acceleration this time for the two different parts(rocket on and off)

thanks it took me 15 or so minutes but i got it

## 1. How is the speed of a rocket leaving a ramp calculated?

The speed of a rocket leaving a ramp is calculated using the equation: speed = distance/time. This means that the speed of the rocket is equal to the distance it travels divided by the time it takes to travel that distance.

## 2. What factors affect the speed of a rocket leaving a ramp?

Several factors can affect the speed of a rocket leaving a ramp, including the angle of the ramp, the amount of force applied to the rocket, and the weight of the rocket itself. Air resistance and other external forces can also impact the speed of the rocket.

## 3. Does the material of the ramp affect the speed of the rocket?

Yes, the material of the ramp can affect the speed of the rocket. A smoother surface, such as a metal ramp, will create less friction and allow the rocket to travel faster. A rougher surface, such as a wooden ramp, will create more friction and slow down the rocket's speed.

## 4. How does the angle of the ramp affect the speed of the rocket?

The angle of the ramp can significantly impact the speed of the rocket. A steeper ramp will result in a faster acceleration, while a shallower ramp will result in a slower acceleration. The optimal angle for maximum speed will depend on the specific rocket and its propulsion system.

## 5. What is the average speed of a rocket leaving a ramp?

The average speed of a rocket leaving a ramp can vary greatly depending on the factors mentioned above. Generally, a rocket leaving a ramp will reach speeds of at least 50 miles per hour, but it is possible for some rockets to reach speeds of over 100 miles per hour if the conditions are ideal.

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