Answer:
B. 24.2 m/s
Explanation:
Given;
mass of the roller coaster, m = 450 kg
height of the roller coaster, h = 30 m
The maximum potential energy of the roller coaster due to its height is given by;



Therefore, the maximum speed of the roller coaster is 24.2 m/s.
Answer:
a) the strong magnetic field inhibits the currents of hot gas rising from below.
Explanation:
Sunspots are dark because they are a little cooler than the photo sphere.
The magnetic field inhibits the strong rising currents of hot gas,allowing it to cool the surface.
Answer:
Pressure applied by the man= 285103.125
or 41.35 
Explanation:
Pressure is defined as the perpendicular force applied per unit area.
i.e. 
Now, 
where,
= mass of the body(man) = 93 kg
= acceleration due to gravity of Earth = 9.81 
covered is equal to the area of both stilts(a man generally stands on two feet)
therefore

and putting in the values, we get,

Now we need to convert to our required units:

(We can get the above result by individually converting kg to lb and meters to inches respectively)
Using the above relations we get,
