24. A 2.0-kg ball is attached to a 0.80 m string and whirled in a horizontal circle at a constant speed of 6.0 m/s.

 

The work done on the ball during each revolution is:

25. Which of the following is NOT possible for the images formed by the lens in the accompanying figure?

 

 

27. A long straight wire conductor is placed below a compass. When the conventional current in the conductor is from south to north and large, the N pole of the compass:

 

 

28. A photon with frequency f behaves as if it had a mass equal to:

 

31. See the accompanying figure.

 

 

What is the current through the 300-ohm resistor when the capacitor is fully charged?

32. The 10.0 kg box shown in the figure below is sliding to the right along the floor. A horizontal force of 10.0 N is being applied to the right. The coefficient of kinetic friction between the box and the floor is 0.20.

 

 

The box is moving with:

33. Two blocks X and Y are in contact on a horizontal frictionless surface. A 36 N constant force is applied to X as shown below.

 

 

The force exerted by X on Y is:

35. A projectile of mass m is fired horizontally from a spring gun that rests on a horizontal frictionless surface. The mass of the gun is M .

 

 

If the kinetic energy of the projectile after firing is E_k, the gun will recoil with a kinetic energy equal to:

36. An isolated conducting sphere of radius R has positive charge +Q. Which graph best depicts the electric field as a function of r, the distance from the center of the sphere?

37. Four identical light bulbs K, L, M, and N are connected in the electrical circuit shown in the accompanying figure. Bulb M burns out.

 

 

Which of the following statements is true?

38. A pendulum bob mass m on a cord length L is pulled sideways until the cord makes an angle θ with the vertical as shown in the figure below.

 

 

The change in potential energy of the bob during the displacement is: