Question
Question: A toy car rolls down the inclined plane as shown in the fig. It goes around the loop at the bottom. ...
A toy car rolls down the inclined plane as shown in the fig. It goes around the loop at the bottom. What is the relation between H and h

A
hH=2
B
hH=3
C
hH=4
D
hH=5
Answer
hH=5
Explanation
Solution
When car rolls down the inclined plane from height H, then velocity acquired by it at the lowest point
v=2gH ….(i)
and for looping of loop, velocity at the lowest point should be v=5gr ….(ii)
From eqn (i) and (ii) v=2gH=5gr ∴H=25r.(iii)
From the figure H=h+2r ⇒ r=2H−h
Substituting the value of r in equation (iii) we get H=25[2H−h] ⇒ hH=5