3. Thermal Energy Find the final temperature when 350 g of zinc at 135 o C is mixed with 650 g of water at 22 o C.

4. (.350)(388)(135-T f ) = (.650)(4180)(T f -22) 18333 - 135.8 T f = 2717 T f – 59774 78107 = 2852.8 T f T f = 27.4 o C

5. Thermal Energy A 415 g sample of unknown metal at 112 o C is placed in 1.2 kg container of methanol at 19.1 o C. The final temperature of the metal and methanol is 28.7 o C. Find the specific heat of the metal.

6. (.415)(c)(112-28.7) = (1.2)(2450)(28.7-19.1) 34.5695(c) = 28224 c = 816 J/Kg o C

7. Efficiency An 1800 W, 40 kg segway propels its 85 kg rider to 35 km/h in 7.6 s. Find the efficiency of the segway.

8. E in = Pt = (1800)(7.6) = 13680 J E out = 1 / 2 mv 2 = (.5)(125)(9.72) 2 = 5907.6 J Eff = E out /E in = 5907.6/13680 x 100% = 43%

9. Work A 120 kg sasquatch runs up a 12 o slope for 50 m to escape from photographers. Determine the amount of work done by the sasquatch.

10. W = Fd F = 120(9.8) = 1176 N d = 50 sin 12 o = 10.4 m W = (1176)(10.4) = 1.22x10 4 J

11. A baseball player throws a 140 gram baseball at a 35 o angle upwards at 38 m/s from the top of a 56 m tall cliff. How fast will the ball be traveling when it hits the ground below?

14. If a gorilla is standing at the top of a 8.0 m tall ladder and throws a banana straight up into the air at 23 m/s, how high will the banana go?

19. A 1200 kg car starts from rest at the top of an 54 m tall hill. Before going off of the hill a tow truck pushes with a force of 8000 N for 23m. After coasting down the hill, the car slams on its brakes and stops in a distance of 116 m. Find the size of the force of friction.

22. An 850 kg small plane starts from rest on the ground. At full power its engine has a power of 105 000 W. How long will it take to reach an altitude of 2500 m and a speed of 40 m/s?