Winter Midterm Review Questions PHYS106 February 24, 2008 PHYS106 () Winter Midterm Review Questions February 24, 2008 1 / 12
MassCenter003 Calculate the position of the mass center of the rigid system shown in the figure that comprises four masses connected by rigid massless rods: m = 1.0 kg and b = 1.0 m. 4m b 4 3 6m y 1 10m 2 0 x b 2m Marks: 1 PHYS106 () Winter Midterm Review Questions February 24, 2008 2 / 12
RotationalDynamics016 A rigid system comprising four masses connected by rigid massless rods (m = 1.0 kg and b = 1.0 m) is pivoted about point P. (a) Calculate the moment of inertia I P. (b) If the system is allowed to pivot about point P, calculate the angular acceleration immediately after it is let go. up 4m b 4 3 6m y 10m 1 2 P x b 2m Marks: 1, 1 PHYS106 () Winter Midterm Review Questions February 24, 2008 3 / 12
RotationalDynamics006 A uniform disk, a thin hoop, and a uniform sphere, all with the same mass (M) and same outer radius (a), are each free to rotate about a fixed axis through its center. Assume the hoop is connected to the rotation axis by light spokes. With the objects starting from rest, identical forces are simultaneously applied to the rims, as shown. Rank the objects according to their angular momenta after a given time t, least to greatest. A. They are all the same B. disk, hoop, sphere C. hoop, disk, sphere D. hoop, sphere, disk E. sphere, disk, hoop disk hoop sphere F F F I disk = 1 2 Ma2 I hoop = Ma 2 I sphere = 2 5 Ma2 PHYS106 () Winter Midterm Review Questions February 24, 2008 4 / 12
RotationalDynamics007 A rod rests on frictionless ice. Forces that are equal in magnitude and opposite in direction are then simultaneously applied to its ends as shown. The quantity that vanishes is its: A. angular momentum B. angular acceleration C. total linear momentum D. kinetic energy E. rotational inertia F F view from above PHYS106 () Winter Midterm Review Questions February 24, 2008 5 / 12
RotationalDynamics008 The rotational inertia of a disk about its axis is 0.70 kg m 2. When a 2.0 kg weight is added to its rim, 0.40 m from the axis, the rotational inertia becomes: A. 0.38 kg m 2 B. 0.54 kg m 2 C. 0.70 kg m 2 D. 0.86 kg m 2 E. 1.0 kg m 2 PHYS106 () Winter Midterm Review Questions February 24, 2008 6 / 12
RotationalDynamics009 A disk with rotational inertia of 5.0 kg m 2 and a radius of 0.25 m rotates on a frictionless fixed axis perpendicular to the disk and through its center. A force of 8.0 N is applied tangentially to the rim. The angular acceleration of the disk is: A. 0.40 rad/s 2 B. 0.60 rad/s 2 C. 1.0 rad/s 2 D. 2.5 rad/s 2 E. 10 rad/s 2 PHYS106 () Winter Midterm Review Questions February 24, 2008 7 / 12
RotationalDynamics010 The rotational inertia of a solid uniform sphere about a diameter is (2/5)MR 2, where M is its mass and R is its radius. If the sphere is pivoted about an axis that is tangent to its surface, its rotational inertia is: A. MR 2 B. (2/5)MR 2 C. (3/5)MR 2 D. (5/2)MR 2 E. (7/5)MR 2 PHYS106 () Winter Midterm Review Questions February 24, 2008 8 / 12
RotationalDynamics017 view from above v bullet m M C a cylinder P rotation axis A cylinder, with mass M = 1.0 kg and radius a = 0.1 m, is positioned so that its symmetry axis, that passes through the center of the cylinder (C), is vertical. It is free to rotate about a parallel axis that passes through point P. If the moment of inertia about the high symmetry axis I c = 1 2 Ma2, (a) calculate the moment of inertia of the cylinder about point P using the parallel axis theorem: I P = I C + Md 2. Marks: 1 PHYS106 () Winter Midterm Review Questions February 24, 2008 9 / 12
RotationalDynamics017 (b) A bullet of mass m = 0.01 kg, moving with speed v = 10.0 ms 1, strikes and becomes embedded in the cylinder at the edge of the cylinder. What is the moment of inertia of the total system cylinder + bullet? (c) Before the collision, the cylinder was at rest. After the bullet strikes the cylinder, it begins to rotate about point P. Assuming no frictional torque, use the conservation of angular momentum to calculate the angular speed ω of the cylinder after the bullet strikes? Winter Midterm 2005 Marks: 1, 1 PHYS106 () Winter Midterm Review Questions February 24, 2008 10 / 12
Electricity019 If the four points shown below (a-d) are ordered from low to high electrostatic potential, which of the following sequences best describes them? (a) dbac (b) dcba (c) dbca (d) cdba (e) none of these. +Q a -Q x x c +Q 2x b -Q 2x d Winter Midterm 2004 Marks: 1 PHYS106 () Winter Midterm Review Questions February 24, 2008 11 / 12
Electricity020 A line charge (λ Q/a) and a point charge (+Q) are located as shown. Only part of the line charge is shown because it is infinite in length. The line charge density λ. (a) Calculate the electric field at P 1 and P 3 due to the line charge alone. (b) Calculate the electric field at P 1 and P 3 due to the point charge alone. (c) Calculate the total electric field at P 1 and P 3 using the fact that λ Q/a. infinite line charge +Q a a a P P P 1 2 3 x Winter Midterm 2004 Marks; 2, 1, 1. PHYS106 () Winter Midterm Review Questions February 24, 2008 12 / 12