A 600 g model rocket is on a cart that is rolling to the right at a speed of 2.5 m/s. The rocket engine, when it is fired, exerts a 8.0 N vertical thrust on the rocket. Your goal is to have the rocket pass through a small horizontal hoop that is 20 m above the launch point.

At what horizontal distance left of the loop should you launch?

8.66 m

Explanation:

600g = 0.6 kg

Let g = 10m/s2. Gravity acting on the rocket model would have a magnitude of:

mg = 0.6*10 = 6 N

When the thrust of 8N acting on the rocket, the net force would be F = 8 - 6 = 2N vertically upward. So the net acceleration according to Newton 2nd law would be

a = F/m = 2 / 0.6 = 3.33 m/s2

We can calculate the time t it would take to reach h = 20m vertically at this acceleration:

Assume that the horizontal speed v = 2.5m/s stays constant, then the horizontal distance from where it starts thrusting up to the loop is

2.5 * 3.46 = 8.66 m

another example of kinetic energy would be,

kinetic energy   >     moving energy

answer   >   letter choice (c),   a hammer falling off a table.

hope that !                                         : )