James and Andrea take a trip in Andrea's car. On the first leg of the trip, they drive 40 miles per hour to their destination. On the second leg, they turn around and return by the same route in 4 hours. How long do they spend driving on the first leg?

Does heating a metal wire increase or decrease its electrical resistance? why?

6. an article, which costs rs. 850 is sold at a profit of 6%.what is the selling price ? -a) rs.900 b) rs. 901 c) rs. 890 d) rs. 905

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).