KEAM 2019 Physics and Chemistry Paper

Key idea Acceleration of block sliding down a rough inclined plane as shown in the figure, is given by
a=g(sin‌θ−µ‌cos‌θ) Given, mass of brick m=2kg,
height of plane H=5m,θ=30∘ and coefficient of friction µ=‌

1

2√3

∴‌‌a=g(sin‌30∘−‌

1

2√3

‌cos‌30∘)
⇒‌‌a=10[‌

1

2

−‌

1

4

]=2.5m/s2
Length of inclined plane
x=H‌sin‌θ=5×sin‌30∘=10m
From 3rd equation of motion
v2−u2=2as
⇒‌‌v=√2as
So, nearby correct option is (c).