Bob is sitting in a homemade space rocket. He knows that if he wants to escape Earth's gravity he is going to have to be traveling at least Mach 33 (33 times the speed of sound or 112 km/s) In his trial data, he averaged 1,807 km in 2.34 minutes. Will he be able to escape Earth's gravitational pull?
The Correct Answer and Explanation is:
To determine if Bob’s rocket will be able to escape Earth’s gravity, we need to compare the speed he is traveling to the required speed, which is 112 km/s (Mach 33).
Step 1: Calculate Bob’s average speed
We are given the following data:
- Distance traveled = 1,807 km
- Time taken = 2.34 minutes
To find Bob’s average speed, we convert the time from minutes to seconds (since we need the speed in km/s):Time in seconds=2.34 minutes×60 seconds/minute=140.4 seconds\text{Time in seconds} = 2.34 \, \text{minutes} \times 60 \, \text{seconds/minute} = 140.4 \, \text{seconds}Time in seconds=2.34minutes×60seconds/minute=140.4seconds
Now, calculate the speed in km/s:Speed=DistanceTime=1,807 km140.4 s≈12.86 km/s\text{Speed} = \frac{\text{Distance}}{\text{Time}} = \frac{1,807 \, \text{km}}{140.4 \, \text{s}} \approx 12.86 \, \text{km/s}Speed=TimeDistance=140.4s1,807km≈12.86km/s
Step 2: Compare the speeds
The required speed to escape Earth’s gravity is 112 km/s (Mach 33), but Bob’s rocket is currently traveling at 12.86 km/s, which is significantly slower.
Conclusion
Bob’s current speed of 12.86 km/s is far below the required 112 km/s, so he will not be able to escape Earth’s gravitational pull with his current speed. He will need to accelerate his rocket significantly to achieve escape velocity.
