Q: A 2.0 kg object is lifted vertically by a woman to a height of 3.0 m. What is the work done by the woman on the object? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

$$W = 2.0 \times 9.8 \times 3.0 = 58.8\ \mathrm{J}$$

Q: A gas expands from $$V_1 = 1.0$$\ \mathrm{L}$$ to V_2$ = 3.0\ \mathrm{L}$$ against a constant external pressure of $$2.0\ \mathrm{atm}. $$What is the work done by the gas? ($$1\ \mathrm{L\cdot atm} = 101.3\ \mathrm{J})$$

$$W = 2.0 \times (3.0 - 1.0) = 4.0\ \mathrm{L\cdot atm} = 405.2\ \mathrm{J}$$

Q: A 0.5 kg ball is thrown vertically upward with an initial speed of $$10\ \mathrm{m/s}. $$What is its kinetic energy at the moment it leaves the hand?

$$K = \frac{1}{2} \times 0.5 \times 10^2$ = 25\ \mathrm{J}$$

Q: A 4.50 g heated metal sample at $$70.0^\circ\mathrm{C} is $$added to 24.0 g of water at $$10.0^\circ\mathrm{C} in an $$insulated container. The heat capacity of water is $$1.00\ \mathrm{cal/g^\circ C}$$, and the final temperature is $$20.0^\circ\mathrm{C}. $$What is the specific heat capacity $$c of $$the metal?

$$c = \frac{24.0 \times 1.00 \times (20.0 - 10.0)}{4.50 \times (70.0 - 20.0)} = 0.1067\ \mathrm{cal/g^\circ C}$$

Question 1

Which of the following best describes the difference between a scalar and a vector quantity?

Accepted Answer

A vector has both magnitude and direction, while a scalar has only magnitude.

Question 2

A 2.0 kg object is lifted vertically by a woman to a height of 3.0 m. What is the work done by the woman on the object? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$W = 2.0 	imes 9.8 	imes 3.0 = 58.8\ \mathrm{J}$$

Question 3

Which of the following is the correct SI unit for pressure?

Accepted Answer

$$1\ \mathrm{Pa} = 1\ \mathrm{N\cdot m$$^{-2}$$}$$

Question 4

A gas expands from $$V_1 = 1.0$$\ \mathrm{L}$$ to V_2$ = 3.0\ \mathrm{L}$$ against a constant external pressure of $$2.0\ \mathrm{atm}. $$What is the work done by the gas? ($$1\ \mathrm{L\cdot atm} = 101.3\ \mathrm{J})$$

Accepted Answer

$$W = 2.0 	imes (3.0 - 1.0) = 4.0\ \mathrm{L\cdot atm} = 405.2\ \mathrm{J}$$

Question 5

Which of the following statements about the work-energy theorem is correct?

Accepted Answer

The work done on a particle by the force acting on it equals the change in its kinetic energy.

Question 6

A 0.5 kg ball is thrown vertically upward with an initial speed of $$10\ \mathrm{m/s}. $$What is its kinetic energy at the moment it leaves the hand?

Accepted Answer

$$K = \frac{1}{2} 	imes 0.5 	imes 10^2$ = 25\ \mathrm{J}$$

Question 7

Which of the following is a conservative force?

Accepted Answer

Gravitational force

Question 8

A system absorbs $$500\ \mathrm{J} of $$heat and does $$200\ \mathrm{J} of $$work on the surroundings. What is the change in internal energy $$\Delta U of $$the system?

Accepted Answer

$$\Delta U = 500 - 200 = 300\ \mathrm{J}$$

Question 9

Which of the following best describes the law of conservation of mechanical energy for a system with only conservative forces?

Accepted Answer

$$E_{\mathrm{mech}} = K + V is $$constant

Question 10

A 4.50 g heated metal sample at $$70.0^\circ\mathrm{C} is $$added to 24.0 g of water at $$10.0^\circ\mathrm{C} in an $$insulated container. The heat capacity of water is $$1.00\ \mathrm{cal/g^\circ C}$$, and the final temperature is $$20.0^\circ\mathrm{C}. $$What is the specific heat capacity $$c of $$the metal?

Accepted Answer

$$c = \frac{24.0 	imes 1.00 	imes (20.0 - 10.0)}{4.50 	imes (70.0 - 20.0)} = 0.1067\ \mathrm{cal/g^\circ C}$$

Question 11

Which of the following is the correct expression for the infinitesimal work $$dw$$ done by a force $$F_x$$ acting over a displacement $$dx in $$one dimension?

Accepted Answer

$$dw = F_x dx$$

Question 12

A piston contains an ideal gas and is compressed reversibly at constant external pressure. Which equation correctly gives the work done on the system?

Accepted Answer

$$w = -P_{\mathrm{ext}} \Delta V$$

Question 13

Which of the following statements about reversible and irreversible processes is correct?

Accepted Answer

Reversible processes require infinitesimal temperature differences.

Question 14

If a system undergoes an isochoric process (constant volume), what is the work done by the system?

Accepted Answer

$$w = 0$$

Question 15

A 1.0 kg object is moving at $$5.0\ \mathrm{m/s}. $$What is its kinetic energy?

Accepted Answer

$$K = \frac{1}{2} 	imes 1.0 	imes 5.0^2$ = 12.5\ \mathrm{J}$$

Question 16

Which of the following is NOT a base SI unit?

Accepted Answer

Joule (J)

Question 17

A system is compressed by its surroundings so that $$\Delta V \u003c 0. $$What is the sign of the work done by the system?

Accepted Answer

Negative

Question 18

Which of the following best describes the total kinetic energy of a multi-particle system?

Accepted Answer

It is the sum of the individual kinetic energies of all particles.

Question 19

Which of the following is true about the total potential energy of a multi-particle system?

Accepted Answer

It is not simply the sum of the individual potential energies due to pairwise interactions.

Fundamental Concepts in Classical Mechanics and Thermodynamics for Physical Chemistry

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