Projectile motion rocket problem

In summary, a rocket is fired at a speed of 75.0 m/s from ground level at an angle of 60.0 degrees above the horizontal. It is aimed towards an 11.0 m high wall, located 27.0 m away. The rocket reaches its launch speed almost immediately and then coasts. Using the equations of motion, the rocket is found to clear the top of the wall by 38.3 m, instead of the expected 33.2 m. This discrepancy is due to using a positive value for the vertical acceleration, when it should be negative as gravity pulls the rocket down. To get the correct answer, the acceleration should be -9.8 m/s^2.
  • #1
mslena79
32
0

Homework Statement


A rocket is fired at at speed fo 75.0 m/s from ground level, at an angle of 60.0 deg. above the horizontal. The rocket is fired toward an 11.0 m high wall, shich is located 27.0 m away. The rocket attains its launch speed in a negligibly short period of time, after which its engines shut down and the rocket coasts. By how much does the rocket clear the top of the wall?


Homework Equations





The Attempt at a Solution


I got the initial vy by 75.0(sin(60))=65.0 m/s, and vx 75.0(cos(60))=37.5 m/s
27.0m=(37.5m/s)t + (1/2*0*t)
t=0.720s
y=65.0 m/s(0.720s) + 1/2(9.80 m/s^2)(0.720^2)
y=49.3m
49.3-11.0=38.3m above the wall
The answer is supposed to be 33.2m, I'm not sure where I went wrong.
 
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  • #2
vertical acceleration = -9.8m/s^2 not 9.8m/s^2
 
  • #3
thanks
 

Related to Projectile motion rocket problem

1. What is projectile motion?

Projectile motion is the motion of an object that is launched into the air and then moves under the influence of gravity alone, with no other external forces acting on it. This type of motion can be seen in objects like rockets, projectiles, and thrown objects.

2. How does a rocket launch affect its trajectory?

A rocket launch affects its trajectory by providing an initial velocity, or speed, to the rocket. This initial velocity, combined with the force of gravity, determines the path that the rocket will follow.

3. What factors affect the trajectory of a rocket?

The trajectory of a rocket is affected by several factors, including the initial velocity, the angle at which it is launched, the air resistance, and the force of gravity. These factors can be manipulated to change the trajectory of the rocket.

4. How can we calculate the trajectory of a rocket?

The trajectory of a rocket can be calculated using the principles of projectile motion. This involves using equations to determine the height, distance, and time of flight for the rocket. Factors like air resistance and wind can also be taken into account to get a more accurate trajectory calculation.

5. Can we predict the landing spot of a rocket based on its initial launch parameters?

Yes, we can predict the landing spot of a rocket based on its initial launch parameters, such as the initial velocity and angle of launch. However, factors like air resistance and wind can also affect the trajectory and landing spot, so these must be taken into consideration as well for a more accurate prediction.

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