What device is used to measure a current through a resistor? How should the device be connected to the resistor? (1K, 1C) What is the difference between a step-down and step-up transformer? (1K, 1C) An electric current in a wire flows from the west to the east. A magnetic field perpendicular to the wire exerts a magnetic force on the wire. The force is directed to the south. What is the direction of the magnetic field? Sketch a diagram. (1A, 1C) Part C. Problems (21A, 10T, 4C) For full marks intermediate steps must be shown. 1) 2) An iceskater applies a horizontal force to a 2.0x10kg block on frictionless level ice, causing the block to accelerate uniformly at 1.4 m/s2 to the right. After the skater stops pushing the block, it slides onto a region of sand-covered ice. The coefficient of kinetic friction between the block and the sandcovered ice is 0.28. a) Determine the force applied to the block by the skater. Draw a free-body diagram. (2A, 1C) b) How long does it take the block to come to a stop if the speed of the block before it enters the sandcovered ice is equal to 4.5 m/s? Draw a free-body diagram. (4A, 1C) A person standing on the roof of a 50.0mhigh building kicks a stone at a horizontal velocity of 4.00 m/s. a) How much time is required for the stone to reach the ground? (2A) b) At what distance from the building does the stone hit the ground? (2 A) c) What is the velocity of the stone before it hits the ground? (3 T) d) Use the law of conservation of energy to find the speed of the stone before it hits the ground. Compare your answers to questions c and d. (3A) 3) How much water at 90C must be added to 250 g of water at 20C to get water with a final temperature of 36C? (4A) 4) An air column closed at one end is 65.0 cm long. Calculate the frequency of fork that will cause resonance at the first harmonic. The temperature of the air is 19C. (4A) l 5) The electromotive force of the R2 battery is equal to 12 V. All three resistors R1 have the same resistance 2.0 0. Determine the current through each resistor and through the battery. Find the potential difference across each resistor. Show all steps of your solution. (7T, 2C)