Bob is pushing a box across the floor at a constant speed of 1.7 m/s, applying a horizontal force whose magnitude is 70 N. Alice is pushing an identical box across the floor at a constant speed of 3.4 m/s, applying a horizontal force. a. What is the magnitude of the force that Alice is applying to the box? F = N b. With the two boxes starting from rest, explain qualitatively what Alice and Bob did to get their boxes moving at different constant speeds. a. In order to keep the box moving twice as fast, Alice had to apply a constant force that was twice as large as the force that Bob applied. b. Each initially applied a force bigger than static friction to get the box moving and accelerating, then when the desired final speed was achieved they reduced the force to make the net force zero.

According to the tide table below what time of day will the highest tide occur?

Part f - example: finding two forces (part i) two 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).

It can take some of those large , industrial vehicles up to feet to stop when traveling only 60 mph, and therefore , you shoukd be mindful to not be jn the traffic right in front of them a. 100 feet b. 200 feet c. 335 feet d. 425 feet