lair set 15 si 7. If you pull up on an insulated bike pump with a force of 500 N
ID: 778203 • Letter: L
Question
lair set 15 si 7. If you pull up on an insulated bike pump with a force of 500 N and the handle moves a distance of 0.4 meters, how will the internal energy of the air inside the pump change? (a) It will decrease by 1250 J (b) It will remain the same. (c) It will decrease by 200 J (d) It will increase by 200 J. 8. Your friend wants to build a huge magnifying gless, so large that it could focus an amount of sunlight that heats a single point on the ground to be twice as hot as the sun. There is a problem with this idea. What is it? (a) Although possible, this requires a magnifying glass with the diameter of the Sun. (b) This would violate the second law of thermodynamics. e) This would violate the first law of thermodynamics (conservation of energy). (d) Temperatures this high are impossible to achieve without nuclear fusion. 10. An engine heats steam to 125°C and gathers energy as heat flows to a cold reservoir out- doors, at 20°C. What is the best efficiency that this engine can achieve? (a) 26.3% (b) 36.4% (c) 84% (d) 525% 11. A small plastic ball with a charge of 3 0-7 C is brought to a distance of 0.02 m away from a second plastic ball. The second plastic ball is repelled with a force of 0.5 N. What is the charge on the second ball? (a)-7.4x10-8 C (b)-3.7 × 10-6C (c) 7.4 x 10- C (d) 3.7 x 10-6 c 12. The figure to the right shows an electron moving in a magnetic field. What is the direction of the force on the electron? (a) Into the page (b) Out of the page (c) No magnetic force (d) Cannot be determined from diagranm 13. A flute with both ends open plays the standing wave shown in the diagram below. What is the frequency of the pitch produced?Explanation / Answer
7)
dQ=dU+dW
0=dU+dW
==> dU=-dW
=-F*s
=-500*0.4
=-200 Jouls
corect option is (c)
8)
correct option is (d)
10)
Th=125 oC
Tc=20 oC
efficiency, = 1-Tc/Th
=1-(20+273)/(125+273)
=0.264 or 26.4%
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.