Q: A uniform rod of length $$2\ \mathrm{m}$$ and mass $$4\ \mathrm{kg} is $$pivoted at one end. What is its moment of inertia about the pivot?

$$\frac{1}{3} mL^2$ = \frac{1}{3} \times 4 \times 4 = 5.33\ \mathrm{kg\cdot m^2$}$$

Question 1

A car travels 60 km north, then 80 km east. What is the magnitude of its displacement vector?

Accepted Answer

$$100\ \mathrm{km}$$

Question 2

A runner accelerates uniformly from rest to a speed of $$8\ \mathrm{m/s} in$$ $$4\ \mathrm{s}. $$What is the runner's acceleration?

Accepted Answer

$$2\ \mathrm{m/s^2$}$$

Question 3

A projectile is launched at an angle of $$30^\circ$$ above the horizontal with an initial speed of $$20\ \mathrm{m/s}. $$What is the maximum height reached by the projectile? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$5.1\ \mathrm{m}$$

Question 4

Which of the following best describes Newton's third law of motion?

Accepted Answer

For every action, there is an equal and opposite reaction.

Question 5

A $$5\ \mathrm{kg}$$ box is pulled across a horizontal surface with a force of $$30\ \mathrm{N} at an $$angle of $$37^\circ$$ above the horizontal. If the coefficient of kinetic friction is $$0.2$$, what is the acceleration of the box? ($$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$2.4\ \mathrm{m/s^2$}$$

Question 6

A $$2\ \mathrm{kg}$$ object is dropped from a height of $$10\ \mathrm{m}. $$What is its kinetic energy just before hitting the ground? (Neglect air resistance, $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$196\ \mathrm{J}$$

Question 7

Which of the following statements about energy conservation is correct?

Accepted Answer

The total mechanical energy of a system is conserved if only conservative forces are acting.

Question 8

A $$0.15\ \mathrm{kg}$$ baseball moving at $$40\ \mathrm{m/s} is $$hit back in the opposite direction at $$60\ \mathrm{m/s}. $$What is the magnitude of the impulse delivered to the ball?

Accepted Answer

$$15\ \mathrm{kg\cdot m/s}$$

Question 9

A uniform rod of length $$2\ \mathrm{m}$$ and mass $$4\ \mathrm{kg} is $$pivoted at one end. What is its moment of inertia about the pivot?

Accepted Answer

$$\frac{1}{3} mL^2$ = \frac{1}{3} 	imes 4 	imes 4 = 5.33\ \mathrm{kg\cdot m^2$}$$

Question 10

A $$500\ \mathrm{kg}$$ car is lifted by a hydraulic lift. If the area of the input piston is $$0.01\ \mathrm{m^2$}$$ and the output piston is $$0.5\ \mathrm{m^2$}$$, what minimum force must be applied to the input piston to lift the car? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$98\ \mathrm{N}$$

Question 11

Which of the following best explains why astronauts in the International Space Station appear weightless?

Accepted Answer

They are in continuous free fall around the Earth.

Question 12

A mass attached to a spring oscillates with a period $$T. If $$the mass is quadrupled, what happens to the period?

Accepted Answer

It doubles.

Question 13

A sound wave travels through air at $$340\ \mathrm{m/s}. If $$its frequency is $$1700\ \mathrm{Hz}$$, what is its wavelength?

Accepted Answer

$$0.2\ \mathrm{m}$$

Question 14

A $$0.5\ \mathrm{kg}$$ block of ice at $$0^\circ\mathrm{C} is $$placed in $$1000\ \mathrm{g} of $$water at $$30^\circ\mathrm{C}. $$What is the final temperature after thermal equilibrium is reached? (Assume no heat loss, $$c_{water} = 4186\ \mathrm{J/kg\cdot K}$$, $$L_f = 334,000\ \mathrm{J/kg})$$

Accepted Answer

$$0^\circ\mathrm{C}$$

Question 15

Which of the following is a correct statement of the first law of thermodynamics?

Accepted Answer

$$\Delta U = Q - W$$

Question 16

A heat engine absorbs $$500\ \mathrm{J} of $$heat and does $$200\ \mathrm{J} of $$work. What is the efficiency of the engine?

Accepted Answer

$$0.4$$

Question 17

Which of the following best describes an adiabatic process?

Accepted Answer

No heat is exchanged with the surroundings.

Question 18

A diver in a swimming pool experiences an increase in pressure as she descends. Which principle explains this phenomenon?

Accepted Answer

Hydrostatic pressure increases with depth: $$P = P_0$ + \rho g h$$

Question 19

A $$2\ \mathrm{kg}$$ mass is attached to a string and swung in a horizontal circle of radius $$1.5\ \mathrm{m} at a $$speed of $$4\ \mathrm{m/s}. $$What is the tension in the string?

Accepted Answer

$$21.3\ \mathrm{N}$$

Question 20

Which of the following is a consequence of the second law of thermodynamics?

Accepted Answer

Heat cannot spontaneously flow from a colder body to a hotter body.

Physics I Course Syllabus: Topics Overview and Study Guide

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