Given that roller coaster is of tear drop shape
So the speed at the top is given as
v = 11 m/s
acceleration at the top is given as
a = 2.9 g
[tex]a = 2.9(9.8) = 28.42 m/s^2[/tex]
now we know the formula of centripetal acceleration as
[tex]a = \frac{v^2}{R}[/tex]
[tex]28.42 = \frac{11^2}{R}[/tex]
[tex]R = 4.26 m[/tex]
PART B)
now if the total mass is given as
m = 2821 kg
now the Net force will be given as
[tex]F = ma[/tex]
[tex]F = 2821 \times 28.42 = 80172.8 N[/tex]
Now by force equation we will have
[tex]F_n + mg = ma[/tex]
[tex]F_n + 2821(9.8) = 80172.8[/tex]
[tex]F_n = 52527 N[/tex]
PART C)
If the radius of the loop is 14 m
speed is given by same v = 11 m/s
now the acceleration is given as
[tex]a = \frac{v^2}{R}[/tex]
[tex]a = \frac{11^2}{14} = 8.6 m/s^2[/tex]
PART D)
Now for normal force at the top is given by force equation
[tex]F_n + mg = ma[/tex]
[tex]F_n + 2821(9.8) = 2821(8.6)[/tex]
so here normal force is coming with negative sign so it will not be possible to complete the circular path in this case
So normal force will be ZERO