Laura Tucker

Physics 111

Exam 2 Review

Mr. Prell

1)A 200 g squirrel is sitting on a tree limb 20 meters above the ground. What is the gravitational potential of the squirrel with respect to the ground?

  1. 0 J
  2. 4 J
  3. 20 J
  4. 39 J
  5. 78 J

2)Α box is pulled across the floor by a horizontal force applied parallel to the floor in the direction of motion. Α force performing no work during the motion is_____.

  1. The applied force
  2. The normal force of the floor on the box
  3. The frictional force
  4. All the above forces perform work during the motion
  5. None of the forces perform work during the motion

3)Α necessary condition for conservation of momentum in a system is that _____.

  1. Energy is conserved
  2. No unbalanced forces act on bodies in the system
  3. No external forces act on the system
  4. The impulse equals the rate of change of momentum

4)Α 16 kg hammer strikes a 20.9 nail with a speed of 9.0 m/s and comes to rest in a time of 6 milliseconds. What is the average force was imparted to the nail by the hammer?

  1. 8*10^3 N
  2. 12*10^3 N
  3. 16*10^3 N
  4. 20*10^3 N
  5. 24*10^3 N

5)Α 3000 kg truck moving to the east at 15 m/s makes a completely inelastic collision with a 2000 kg car moving north at 25 m/s. Determine the speed of the car truck combination after the collision.

  1. 7.3 m/s
  2. 9.8 m/s
  3. 13.5 m/s
  4. 17.2 m/s
  5. 22.3 m/s

6)Three point masses are in a system. The first at (0,10) with a mass of 4 kg, the second at (3,0) with a mass of 5 kg, and the third at (-3,0) with a mass of 5 kg. What is the y coordinate of the system’s center of mass? Assume all coordinates are in meters.

  1. 1.3 m
  2. 2.9 m
  3. 5.0 m
  4. 7.5 m
  5. 10 m

7)Α student exerts a force of 60 Ν .83m from the door knob at a on a 90 kg door at an angle of 40 degrees as shown to the right. What is the magnitude of the torque she exerts on the door?

  1. 18 Nm
  2. 25 Nm
  3. 31 Nm
  4. 37 Nm
  5. 46 Nm

8)Α uniform wooden sphere and a uniform wooden cylinder roll down an inclined plane without slipping. Both objects have the same mass and radius. Which object reaches the bottom first?

  1. The sphere
  2. The sphere
  3. The cylinder
  4. The reach the bottom at the same time
  5. Problem cannot be solved

9)In a class demonstration the lecturer stood on a platform. He held a bicycle wheel and a student made the wheel rotate at a rapid rate. The lecturer then stepped on the platform holding the rotating wheel. The lecturer thus began to rotate and when he turned the wheel upside down ____.

  1. He rotated faster
  2. His rotation rate remained constant
  3. His rotation stopped
  4. His rotation reversed direction

10)How much force must a person exert vertically downward on the end of the 50 kg uniform board that is 5 m long and where the fulcrum is 3 meters from the right side of the board?

  1. 12 N
  2. 32 N
  3. 67 N
  4. 95 N
  5. 122 N

11)Dominic is the star discus thrower on South's varsity track and field team. In last year's regional competition, Dominic whirled the 1.6 kg discus in a circle with a radius of 1.1 m, ultimately reaching a speed of 52 m/s before launch. Determine the net force acting upon the discus in the moments before launch.

  1. 2.3 * 10^3 N
  2. 2.9 * 10^3 N
  3. 3.1 * 10^3 N
  4. 3.9 * 10^3 N
  5. 4.2 * 10^3 N

12)An 82-kg male and a 48-kg female pair figure skating team are gliding across the ice at 7.4 m/s, preparing for a throw jump maneuver. The male skater tosses the female skater forward with a speed of 8.6 m/s. Determine the speed of the male skater immediately after the throw.

  1. 5.6 m/s
  2. 6.1 m/s
  3. 6.7 m/s
  4. 7.3 m/s
  5. 7.9 m/s

13)A racket exerted an average force of 152.0 N on a ball initially at rest. If the ball has a mass of 0.070 kg and was in contact with the racket for 0.030 s, what was the kinetic energy of the ball as it left the racket?

  1. 60 Joules
  2. 70 Joules
  3. 80 Joules
  4. 90 Joules
  5. 100 Joules

14)What is the rotational inertia of a solid iron disk of mass 49 0 kg with a thickness of 5 00 cm solid iron disk of mass and a radius of 20.0 cm, about an axis through its center and perpendicular to it?

  1. .87 kg * m^2
  2. .91 kg * m^2
  3. .98 kg * m^2
  4. 1.04 kg * m^2
  5. 1.09 kg * m^2

15)Find the moment of inertia of the system below. The masses are m1 an d m 2 and they are separated by a distance r. Assume the rod connecting the masses is massless. ( moving ccw)Take m1 = 2.00 kg, m2 = 1.00 kg, r1= 0.33 m left, and r2 = 0.67 m right. Does the moment of inertia increase or decrease if the axis of movement was changed to mass through m1?

  1. .67 kg* m^2 ; Increase
  2. .67 kg* m^2 ; Decrease
  3. .89 kg* m^2 ; Increase
  4. .89 kg* m^2 ; Decrease
  5. .89 kg* m^2 ; Constant