A 50-Kg Air Conditioner Is Placed on Top of a Concrete

Multiple Choice

A 50-kg air conditioner is placed on top of a concrete pad that is 20 cm thick and has a cross-sectional area of $3.0 \mathrm {~m} ^ { 2 }$ What is the change in thickness of the pad caused by the air conditioner? Young's modulus for concrete is $2.3 \times 10 ^ { 10 } \mathrm {~N} / \mathrm { m } ^ { 2 }$

A) $1.4 \times 10 ^ { - 9 } \mathrm {~m}$
B) $2.8 \times 10 ^ { - 9 } \mathrm {~m}$
C) $1.4 \times 10 ^ { - 7 } \mathrm {~m}$
D) $2.8 \times 10 ^ { - 8 } \mathrm {~m}$
E) $1.4 \times 10 ^ { - 8 } \mathrm {~m}$