4. A small object of mass m is suspended from a string of length L . The
gravitational acceleration is g. The object revolves in a horizontal circle of
radius r with constant speed. Find the period T of revolution.

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50 (A) tour (B) tourism (C) tourist (D) touring

1. A particle moves in a track and its speed are recorded and plotted inthe figure. Which statement is correct? (A) It is stationary from t=0.0 to t=0.5 second.(B) It has maximum acceleration at t=1.5 seconds.(C) No external force acting on the particle at t＞2.5 seconds.(D) The maximum force received by this particle is at t=1.5 seconds.(E) This particle received a constant force against its motion during 1.0 to 2.0 seconds.

2. A particle moves in simple harmonic motion according to x = 2sin(15t), where x is in meters and t is in seconds. Its maximum velocity in m/s is _____.(A) 30 sin(15t) (B) 2 cos(15t) (C) 15(D) 30 (E) None of the above.

3. Consider a very small hole in the bottom of a tank 20 cm in diameter filled with water to a heightof 50 cm. Find the speed at which the water exits the tank through the hole.(A) 3.1 m/s (B) 9.8 m/s (C) 31.3 m/s (D) 34.9 m/s (E) 980 m/s

5. A carnival merry-go-round rotates about a vertical axis at a constant rate. A man standing on theedge has a constant speed of 3.7 m/s and a centripetal acceleration of magnitude 1.8 m/s2.Position vector locates him relative to the rotation axis. What is the magnitude of ?(A) 3.5 m (B) 5.6 m (C) 6.4 m (D) 7.6 m (E) 12.4 m

6. A 2 kg object is subjected to three forces that give it an acceleration = (−8 m  ⁄s2 )+(6 m/s2) . ff two of the three forces are and ,find the third force.(A) (B) (C)(D) (E)

7. n moles of gas in a container of volume at temperature T expands rapidly into an evacuatedregion after a membrane is broken. The final volume of the gas-occupied space is . What is thechange in thermal energy? (The universal gas constant is R.)(A) (B) (C)(D) (E)

8. A medical defibrillator stores 320 J in a 40.0 F capacitor. What is the voltage across the capacitor?(A) 2.8 V (B) 4.0 V (C) 2.8 kV (D) 4.0 kV (E) 2.8 MV

9. The figure shows three electric charges labeled Q1, Q2, Q3, and someelectric field lines in the region surrounding the charges. What are thesigns of the three charges?(A) Q1 is negative, Q2 is positive, Q3 is negative.(B) Q1 is positive, Q2 is positive, Q3 is negative.(C) Q1 is positive, Q2 is negative, Q3 is positive.(D) Q1 is positive, Q2 is negative, Q3 is negative.(E) Q1 is negative, Q2 is negative, Q3 is negative.

10. A particle experiences a force given by F(x) = α - βx3. Find the potential energy U(x) of the particle.(Assume that the zero of potential energy is located at x = 0.)(A) (B) (C) U(x) = 3βx2(D) U(x) = -3βx2 (E) U(x) = -6βx