The space shuttle has a mass of 2.0 x 106 kg. At lift-off, the engines...

Question

The space shuttle has a mass of 2.0 x 106 kg. At lift-off, the engines generate an upward force of 3.0 x 107 N.
a. What is the acceleration of the shuttle?

b. If the shuttle is in outer space with the same thrust force, how would the acceleration change? Explain why this is so using Newton's Laws

Answer 1

Miguel,

The equation to use is F = ma, but we must remember to subtract the force of gravity (weight) from the force of the engines.

 

3x10⁷ - 9.81(2x10⁶) = (2x10⁶)a

5.2 m/s² = a

 

As the shuttle gets farther and farther from the earth, it burns more and more fuel, even dropping massive tanks along the way. So not only does it weigh less, giving gravity less influence, but the reduce mass means less inertial resistance to the acceleration.  Look at F = ma, if F is the same and m decreases, a must increase.