08:38
University Physics with Modern Physics
A small $8.00 \mathrm{~kg}$ rocket burn fuel that exerts a time-varying upward force on the rocket (assume constant mass) as the rocket moves upward from the launch pad. This force obeys the equation $F=A+B t^{2} .$ Measurements show that at $t=0,$ the force is $100.0 \mathrm{~N}$ and at the end of the first $2.00 \mathrm{~s}$, it is $150.0 \mathrm{~N}$. (a) Find the constants $A$ and $B$, including their SI units. (b) Find the net force on this rocket and its acceleration (i) the instant after the fuel ignites and (ii) $3.00 \mathrm{~s}$ after the fuel ignites. (c) Suppose that you were using this rocket in outer space, far from all gravity. What would its acceleration be 3.00 s after fuel ignition?