physics
posted by jo .
Here's a physics problem. I don't care about the answer, i just want to know how to do it. don't have to be too detailed.. but i don't really kno how to start this
1.) A model rocket blasts off from the ground rising straight upward with a constant acceleration that has a magnitude of 86 m/s^2 for 1.70 seconds, at which point fuel runs out. Air resistance neglected What maximum altitude will the rocket reach?
2.)In reaching her destination, a backpacker walks with an average velocity of 1.34 m/s, due west. This average velocity of 2.68 m/s, due west,,turns around and hikes with an average velocity of 0.447 m/s due east. how far did she walk?

1. Using the acceleration and time, calculate the velocity and height at fuel burnout. Then figure the height the rocket can go above this with that initial velocity. Add the heights to get the maximum altitude.
Here is a second way.
Energy put into rocket = change in PE
Force*distance=mgh
Mass*acceleration*distance= mgh
but distance= avgvelocity*time
= (Vf/2)*time=a*t^2/2
Mass*acceleration*acceleration*t^2=mgh
h= a^2/2g * t^2 where t is the time the rocket was accelerating.
check both ways.
2.Makes no sense to me. 
okay. so regarding number 1. I will use the first method. So I will calculate using this formula?
x = v0t + 1/2at^2,
in which case.. x = 86(1.70) + 1/2(10)(1.70)^2? I get x, which would be the position.. how do figure out the height over initial velocity? do i plus 0 in for v0?
Respond to this Question
Similar Questions

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 … 
physics
Here's a physics problem. I don't care about the answer, i just want to know how to do it. don't have to be too detailed.. but i don't really kno how to start this 1.) A model rocket blasts off from the ground rising straight upward … 
physics
Here's a physics problem. I don't care about the answer, i just want to know how to do it. don't have to be too detailed.. but i don't really kno how to start this 1.) A model rocket blasts off from the ground rising straight upward … 
physics
A model rocket is launched straight upward with an initial speed of 51.6 m/s. It accelerates with a constant upward acceleration of 1.96 m/s2 until its engines stop at an altitude of 230 m. What is the maximum height reached by the … 
Physics
An astronaut is inside a rocket that is blasting off vertically from the launch pad. You want this rocket to reach the speed of sound (331 m/s) as quickly as possible, but you also do not want the astronaut to black out. Medical tests … 
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, … 
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
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 … 
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 … 
Physics
A model rocket is launced from the ground with an initial velocity of 65 m/s directly upwards. If a horizontal wind is blowing at 5 m/s during the flight, how far from the launch point will the rocket land?