Math Problem Statement

A rocket is launched with some initial velocity and travels with constant acceleration of 26.3m/s^2. When the rocket has reached a height of 170m above its launch position, its velocity is 197m/s. How long did it take the rocket to reach its height?

Solution

To solve for the time it took the rocket to reach a height of 170 meters, we can apply the kinematic equations of motion. The key equation that relates displacement (ss), initial velocity (uu), acceleration (aa), and time (tt) is:

v=u+atv = u + at s=ut+12at2s = ut + \frac{1}{2} a t^2

Where:

  • v=197m/sv = 197 \, \text{m/s} is the final velocity,
  • uu is the initial velocity (which we do not know),
  • a=26.3m/s2a = 26.3 \, \text{m/s}^2 is the constant acceleration,
  • s=170ms = 170 \, \text{m} is the displacement (height),
  • tt is the time (what we are solving for).

First, we can use the following kinematic equation that does not require time directly:

v2=u2+2asv^2 = u^2 + 2as

Solving for uu (the initial velocity):

u2=v22asu^2 = v^2 - 2as

Substituting the given values:

u2=(197)22×26.3×170u^2 = (197)^2 - 2 \times 26.3 \times 170

Let me calculate this.We found that u2=29867u^2 = 29867, so the initial velocity uu is:

u=29867172.88m/su = \sqrt{29867} \approx 172.88 \, \text{m/s}

Now, using the first kinematic equation:

v=u+atv = u + at

We can solve for tt:

t=vuat = \frac{v - u}{a}

Substituting the values:

t=197172.8826.3t = \frac{197 - 172.88}{26.3}

I'll calculate the value of tt.The time it took the rocket to reach the height of 170 meters is approximately 0.92seconds0.92 \, \text{seconds}.

Would you like more details or have any questions? Here are some related questions you might consider:

  1. How would the time change if the acceleration were different?
  2. What is the rocket’s velocity after 5 seconds of flight?
  3. What would the displacement be after 3 seconds?
  4. How long would it take to reach 500 meters height with the same conditions?
  5. What is the significance of the initial velocity in determining the flight path?

Tip: Always check the units in kinematic problems to ensure consistency between velocity, acceleration, and time.

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Math Problem Analysis

Mathematical Concepts

Kinematics
Constant Acceleration Motion
Displacement
Velocity

Formulas

v^2 = u^2 + 2as
v = u + at
s = ut + 0.5 * a * t^2

Theorems

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Suitable Grade Level

Grades 9-12