Question

A body is moving down a long inclined plane of slope 37⁰. The coefficient of friction between the body and plane varies as m = 0.3x, where x is the distance travelled down the plane. The body will have maximum speed -

(sin 37⁰ = $\left( \frac { 3 } { 5 } \right)$ and g = 10 m/s²)

• A. At x = 1.16 m
• B. At x = 2 m
• C. At bottom of plane
• D. At x = 2.5 m

Answer 1

Answer: (D)

At x = 2.5 m

Answer 2

After some time friction becomes more than mgsinq, then body will retard. Thus speed is maximum when, total force or acc. is zero.

mgsinq – mmgcosq = 0

̃ m = tanq ̃ 0.3x = ¾

̃ x = 2.5m