When the truck broke through the guardrail it was launched from the freeway with a horizontal velocity of 10.7 m/s and fell a vertical distance of 50 feet (15.2 m). a) Draw a simplified sketch showing the trajectory of the truck being launched horizontally with the velocity of 10.7 m/s. b) Determine the time that it would take for the truck to freefall the 50 feet( 15.2 m). c) Ignoring air resistance and scraping the building on the way down, determine the instantaneous velocity of the truck just before impacting the ground.

Wo dimensional dynamics often involves solving for two unknown quantities in two separate equations describing the total force. the block in (figure 1) has a mass m=10kg and is being pulled by a force f on a table with coefficient of static friction îľs=0.3. four forces act on it: the applied force f (directed î¸=30â above the horizontal). the force of gravity fg=mg (directly down, where g=9.8m/s2). the normal force n (directly up). the force of static friction fs (directly left, opposing any potential motion). if we want to find the size of the force necessary to just barely overcome static friction (in which case fs=îľsn), we use the condition that the sum of the forces in both directions must be 0. using some basic trigonometry, we can write this condition out for the forces in both the horizontal and vertical directions, respectively, as: fcosî¸â’îľsn=0 fsinî¸+nâ’mg=0 in order to find the magnitude of force f, we have to solve a system of two equations with both f and the normal force n unknown. use the methods we have learned to find an expression for f in terms of m, g, î¸, and îľs (no n).