HEL!!! It is crash-test-dummy Ed's first day on the job. He (and his 50-kg mass) gets to try out the new 1,200-kg Porsche 911. Lucky Ed! He has to drive it into a brick wall. Unlucky Ed! But it's his job, so he does it. The Porsche and Ed are moving 30 m/s when they collide with the wall, with an impulse time of 0.5 s.

1. What is the magnitude of their initial momentum? (4 points)

2. What is the magnitude of their final momentum? (3 points)

3. What is the magnitude of the impulse of the collision? (3 points)

Acommon procedure for measuring the velocity of an airstream involves the insertion of an electrically heated wire (called a hot-wire anemometer) into the airflow, with the axis of the wire oriented perpendicular to the flow direction. the electrical energy dissipated in the wire is assumed to be transferred to the air by forced convection. hence, for a prescribed electrical power, the temperature of the wire depends on the convection coefficient, which, in turn, depends on the velocity of the air. consider a wire of length l = 20 mm and diameter d = 0.5 mm, for which a calibration of the form v = 6.25 ă— 10â’5 h2 has been determined. the velocity v and the convection coefficient h have units of m/s and w/m2 â‹… k, respectively. in an application involving air at a temperature of tâž = 25â°c, the surface temperature of the anemometer is maintained at ts = 75â°c with a voltage drop of 5 v and an electric current of 0.1 a. what is the velocity of the air?