1. Julie throws a rock vertically upward from a height of 64.0 meters above the ground. The initial velocity of the rock is 31.0 meters per second. Neglect air resistance. (a) How long does it take for the rock to hit the ground? (b) What is the velocity of the rock just before it hits the ground? 64.0 m 2 . The atmospheric pressure is 101,300 pascals and the density of seawater is 1025 kg/m . Find the pressure exerted on an ocean Pa'= 101,300 pascals . diver who is at a depth of 18 meters. 18 m 3. A fire starts from rest and rolls without slipping downhill at a constant acceleration of 13.6 m/s-. The diameter of the tire is 170 cm. (a) Find the angular acceleration of the tire. (b) How long does it take for the tire to reach an angular speed of 51.2 radians per second? 4. A tree branch is floating in water as shown in the diagram. The total volume of the branch is 1:12 m , and 75.0 percent of the volume is submerged (Pwater = 1000 kg/m?). (a) Find the mass of water displaced by the branch. (b) Find the magnitude of the buoyancy force of water. (c) Find the weight of the branch. (d) Find the mass of the branch. 5. In the simple circuit shown, V = 32 V and R = 50 0. (a) Find the current / through the resistor R. 3 R (b) How many electrons pass through the resistor R every second? Physics by Saxon ght @ 1993 by Saxon Publishers, Inc. Reproduction for resale prohibited