QUESTION Neglecting air friction and lift effects, is the time a projectile by a horizontal acceleration stays in the air longer, shorter, or the same as for a projectile that is freely falling?
Longer, the same or shorter?
PRACTICE IT
Use the worked example above to help you solve this problem. A jet plane traveling horizontally at v 0x =1.20*102 m/s drops a rocket from a considerable height (see figure). The rocket immediately fires its engines, accelerating at 22.0 m/s2 in the x-direction while falling under the influence of gravity in the y-direction. When the rocket has fallen 1.00 km, find the following.
1) Its velocity in the y-direction
m/s
2) Its velocity in the x-direction
m/s
3) The magnitude and direction (counter clockwise from the +x-axis) of its velocity. Neglect air drag and aerodynamic lift.
Magnitude m/s
Direction °
EXERCISE:
Assume a rocket-propelled motorcycle is fired from rest horizontally across a canyon 1.30 km wide.
1) What minimum constant acceleration in the x-direction must be provided by the engines so the cycle crosses safely if the opposite side is 0.660 km lower than the starting point?
m/s2
2) At what speed does the motorcycle land if it maintains this constant horizontal component of acceleration? Neglect air drag, however remember that gravity is still acting in the negative y-direction.
m/s