Math Problem Statement

A car travels a distance 166m +-2m in 5.2s +-0.1. What is the best estimate of the speed of the car

Solution

To find the best estimate of the speed of the car, we can use the formula for speed:

Speed=DistanceTime\text{Speed} = \frac{\text{Distance}}{\text{Time}}

Given:

  • Distance d=166m±2md = 166 \, \text{m} \pm 2 \, \text{m}
  • Time t=5.2s±0.1st = 5.2 \, \text{s} \pm 0.1 \, \text{s}

Best estimate of speed:

Speed=166m5.2s31.92m/s\text{Speed} = \frac{166 \, \text{m}}{5.2 \, \text{s}} \approx 31.92 \, \text{m/s}

Now, we calculate the uncertainty in the speed.

Uncertainty in speed:

The relative uncertainty of the speed is the sum of the relative uncertainties of the distance and time:

Δvv=Δdd+Δtt\frac{\Delta v}{v} = \frac{\Delta d}{d} + \frac{\Delta t}{t}

Substituting values:

  • Uncertainty in distance Δd=2m\Delta d = 2 \, \text{m}
  • Uncertainty in time Δt=0.1s\Delta t = 0.1 \, \text{s}

Δvv=2166+0.15.20.01205+0.01923=0.03128\frac{\Delta v}{v} = \frac{2}{166} + \frac{0.1}{5.2} \approx 0.01205 + 0.01923 = 0.03128

Now, multiply this by the best estimate of speed:

Δv=0.03128×31.92m/s0.998m/s\Delta v = 0.03128 \times 31.92 \, \text{m/s} \approx 0.998 \, \text{m/s}

Final result:

Speed=31.92m/s±1.00m/s\text{Speed} = 31.92 \, \text{m/s} \pm 1.00 \, \text{m/s}

Thus, the best estimate of the speed of the car is 31.92m/s±1.00m/s31.92 \, \text{m/s} \pm 1.00 \, \text{m/s}.

Would you like more details or have any questions?

Here are five related questions you might explore:

  1. How does the uncertainty affect the accuracy of the result?
  2. How can we reduce uncertainty in both distance and time measurements?
  3. What would the speed be if the distance were 10 meters shorter?
  4. How would the speed change if the time increased by 0.2 seconds?
  5. What is the significance of relative uncertainties in real-world measurements?

Tip: Always aim to minimize uncertainties by improving the precision of your measurements for better accuracy in calculated results.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Kinematics
Uncertainty in Measurements
Relative Uncertainty

Formulas

Speed = Distance / Time
Relative Uncertainty: Δv/v = Δd/d + Δt/t
Uncertainty in Speed: Δv = Relative Uncertainty × Speed

Theorems

Propagation of Uncertainties

Suitable Grade Level

Grades 10-12