Question 1

A solid uniform ball with a mass of $$0.125\ \mathrm{kg} is $$rolling without slipping along a horizontal surface at $$4.5\ \mathrm{m/s}$$ and falls off a table $$1.1\ \mathrm{m}$$ high. What is the rotational kinetic energy of the ball just before it hits the floor?

Accepted Answer

$$0.51\ \mathrm{J}$$

Question 2

A solid cylinder with mass $$1.2\ \mathrm{kg}$$ and radius $$0.2\ \mathrm{m} is $$released from a spring compressed $$0.1\ \mathrm{m}$$ with spring constant $$150\ \mathrm{N/m}. $$The moment of inertia is $$I = 0.5mr^2$. What is the angular velocity when it starts spinning?

Accepted Answer

$$5.10\ \mathrm{rad/s}$$

Question 3

A torque of $$12\ \mathrm{Nm} is $$applied to a solid, uniform disk of radius $$0.50\ \mathrm{m}. If $$the disk accelerates at $$1.6\ \mathrm{$$rad/s^2$$}$$, what is the mass of the disk?

Accepted Answer

$$60\ \mathrm{kg}$$

Question 4

An odd-shaped object $$12\ \mathrm{m}$$ long is placed with each end on a scale. The right scale reads $$120\ \mathrm{N}$$ and the left reads $$80\ \mathrm{N}. $$How far from the left end is the center of gravity?

Accepted Answer

$$6.5\ \mathrm{m}$$

Question 5

A beam of light enters a thick plastic sheet from air at $$32^\circ$$ with the normal and continues at $$23^\circ$$ with the normal. What is the index of refraction of the plastic?

Accepted Answer

$$1.11$$

Question 6

The index of refraction of glass is $$1.50$$ and of water is $$1.33. If $$light enters water from glass, the angle of refraction will be:

Accepted Answer

greater than the angle of incidence

Question 7

When an object is $$12\ \mathrm{cm} in $$front of a concave mirror, the image is $$3.0\ \mathrm{cm} in $$front of the mirror. What is the focal length of the mirror?

Accepted Answer

$$4.0\ \mathrm{cm}$$

Question 8

A coin is $$12\ \mathrm{cm} in $$front of a converging lens with a focal length of $$4.0\ \mathrm{cm}. $$Where is the image located?

Accepted Answer

$$8.0\ \mathrm{cm}$$ behind the lens

Question 9

A biconvex lens made of glass with index of refraction $$1.50$$ has radii of curvature $$40\ \mathrm{cm} ($$front) and $$30\ \mathrm{cm} ($$back). What is the focal length of this lens?

Accepted Answer

$$11\ \mathrm{cm}$$

Question 10

Which force applied to a door (all with equal magnitude) produces the largest torque?

Accepted Answer

A force applied perpendicular to the door at the farthest point from the hinge

Question 11

A rotating disk slows down due to friction. Which physical quantity is NOT conserved?

Accepted Answer

Angular momentum

Question 12

A $$2.0\ \mathrm{kg}$$ mass is attached to a string and swung in a horizontal circle of radius $$1.5\ \mathrm{m} at$$ $$4.0\ \mathrm{m/s}. $$What is the angular momentum about the center?

Accepted Answer

$$12\ \mathrm{kg\cdot m^2$/s}$$

Question 13

A $$0.5\ \mathrm{kg}$$ hoop of radius $$0.4\ \mathrm{m}$$ rolls without slipping at $$2.0\ \mathrm{m/s}. $$What is its total kinetic energy?

Accepted Answer

$$2.0\ \mathrm{J}$$

Question 14

A $$3.0\ \mathrm{kg}$$ mass is $$2.0\ \mathrm{m}$$ from the axis, a $$2.0\ \mathrm{kg}$$ mass is $$1.0\ \mathrm{m}$$ from the axis, and a $$1.0\ \mathrm{kg}$$ mass is $$1.5\ \mathrm{m}$$ from the axis. What is the moment of inertia about the axis?

Accepted Answer

$$17.25\ \mathrm{kg\cdot m^2$}$$

Question 15

A $$0.2\ \mathrm{kg}$$ mass is attached to a string and swung in a vertical circle of radius $$0.5\ \mathrm{m}. $$What is the minimum speed at the top to keep the string taut?

Accepted Answer

$$1.0\ \mathrm{m/s}$$

College Physics Final Test Review: Rotational Motion, Dynamics, Electromagnetic Waves, and Geometric Optics

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