Question

The coefficient of friction between a body and the surface of an inclined plane at 45° is 0.5. If $g = 9.8 \mathrm {~m} / \mathrm { s } ^ { 2 }$ , the acceleration of the body downwards in $m / s ^ { 2 }$ is

• A. $\frac { 4.9 } { \sqrt { 2 } }$
• B. $4.9 \sqrt { 2 }$
• C. $19.6 \sqrt { 2 }$
• D. 4.9

Answer 1

Answer: (A)

$\frac { 4.9 } { \sqrt { 2 } }$

Answer 2

$a = g ( \sin \theta - \mu \cos \theta ) = 9.8 \left( \sin 45 ^ { \circ } - 0.5 \cos 45 ^ { \circ } \right)$

$= \frac { 4.9 } { \sqrt { 2 } } m / \mathrm { sec } ^ { 2 }$