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1.Calculate U of a gas for a process in which the gas absorbs 9 J of heat from i

ID: 546688 • Letter: 1

Question

1.Calculate U of a gas for a process in which the gas absorbs 9 J of heat from its
surroundings and does 25 J of work by expanding. (NOTE: U is the internal energy of the gas).
A) 16 J B) 34 J C) 175 J D) –34 J E) –16 J

2.

The kinetic energy of a moving object equals one-half its mass times its velocity
squared (KE = 12 mv2

). What is the kinetic energy in joules of a 2000-lb car traveling

at 48 miles per hour? One joule is one kg·m2
·sec–2
(1 lb = 0.4536 kg, 1 mi = 1.609 km)

A) 2.1 x 10–7

J B) 1.0 x 106

J C) 3.5 x 1019 J D) 2.1 x 105

J E) 3.1 x 10–8
J

Explanation / Answer

1)

Q = + 9 J (positive because system absorbs heat)

W = - 25 J (negative because system release heat)

use:

U = Q + W

= 9 J - 25 J

= - 16 J

Answer: - 16 J

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