OC userin Physics·12 Nov 20171.8. While driving in an exotic foreign land, you see a speed limit sign that reads 180,000 furlongs per fortnight. How many miles per hour is this? (One furlong is g mile, and a fortnight is 14 days. A fur- long originally referred to the length of a plowed furrow.)
OC userin Physics·11 Nov 20175.25. BIO The Trendelenburg Position. After emergencies with major blood loss, a patient is placed in the Trendelenburg po- sition, in which the foot of the bed is raised to get maximum blood flow to the brain. If the coefficient of static friction between a typical patient and the bedsheets is 1.20, what is the maximum angle at which the bed can be tilted with respect to the floor be- fore the patient begins to slide?
OC userin Physics·9 Nov 2017Q5.9 A crate slides up an inclined ramp and then slides down the ramp after momentarily stopping near the top. There is kinetic friction between the surface of the ramp and the crate. Which is greater? () The crate's acceleration going up the ramp; (ii) the crate's acceleration going down the ramp; (iii) both are the same. Explain.
OC userin Physics·9 Nov 2017Figure E5.8 5.8 A 1130-kg car is held in place by a light cable on a very smooth (frictionless) ramp (Fig. E5.8). The cable makes an angle of 31.0° above the sur- face of the ramp, and the ramp itself rises at 25.0° above the horizontal. (a) Draw a free-body diagram for the car. (b) Find the tension in the cable. (c) How hard does the surface of the ramp push on the car? 25.00
OC userin Physics·11 Nov 201731.13" A150-resistor is connected in series with a 0.250-H inductor and an ac source. The voltage across the resistor is UR = (3.80 V)cos[(720 rad/s)t]. (a) Derive an expression for the circuit current. (b) Determine the inductive reactance of the inductor. (c) Derive an expression for the voltage UL across the inductor.
OC userin Physics·9 Nov 201714.8. In a physics lab, you attach a 0.200-kg air-track glider to the end of an ideal spring of negligible mass and start it oscillating. The elapsed time from when the glider first moves through the equilibrium point to the second time it moves through that point is 2.60 s. Find the spring's force constant.
OC userin Physics·8 Nov 201731.11 - A 0.180-H inductor is connected in series with a 90.0-12 resistor and an ac source. The voltage across the inductor is v. = -(12.0 V)sin((480 rad/s)t]. a) Derive an expression for the voltage Ur across the resistor. (b) What is up at t = 2.00 ms?
OC userin Physics·9 Nov 20172.36 A small rock is thrown vertically upward with a speed of 22.0 m/s from the edge of the roof of a 30.0-m-tall building. The rock doesn't hit the building on its way back down and lands on the street below. Ignore air resistance. (a) What is the speed of the rock just before it hits the street? (b) How much time elapses from when the rock is thrown until it hits the street?
OC userin Physics·8 Nov 201787. Calculate the number of atoms in each sample. a. 5.18 g P b . 2.26 g Hg c. 1.87 g Bid. 0.082 g Sr
OC userin Physics·5 Nov 20171.3. How many nanoseconds does it take light to travel 1.00 ft in vacuum? (This result is a useful quantity to remember.)
OC userin Physics·3 Nov 20179.9. A bicycle wheel has an initial angular velocity of 1.50 rad/s. (a) If its angular acceleration is constant and equal to 0.200 rad/s?, what is its angular velocity at t = 2.50 s? (b) Through what angle has the wheel turned between t = 0 and t = 2.50 s?
OC userin Physics·3 Nov 20171.53 • BIO Breathing Oxygen. The density of air under stan- dard laboratory conditions is 1.29 kg/m", and about 20% of that air consists of oxygen. Typically, people breathe about 1 L of air per breath. (a) How many grams of oxygen does a person breathe in a day? (b) If this air is stored uncompressed in a cubical tank, how long is each side of the tank?
OC userin Physics·3 Nov 201742. Calculate the pH of the solution that results from each mixture. a. 150.0 mL of 0.25 M HF with 225.0 mL of 0.30 M NaF b. 175.0 mL of 0.10 M C2H5NH2 with 275.0 mL of 0.20 M C2H5NH3C1
OC userin Physics·3 Nov 201788. Calculate the number of atoms in each sample. a. 14.955 g CT b. 39.733 g S c. 12.899 g Pt d . 97.552 g Sn
OC userin Physics·2 Nov 20175.17 . A light rope is attached to a block with mass 4.00 kg that rests on a frictionless, horizontal surface. The horizontal rope passes over a frictionless, massless pulley, and a block with mass m is suspended from the other end. When the blocks are released, the tension in the rope is 15.0 N. (a) Draw two free-body diagrams: one for each block. (b) What is the acceleration of either block? (c) Find m. (d) How does the tension compare to the weight of the hanging block?