As per the first question we have to calculate the height at which the boulder is present.
we have been given the mass of the boulder [m] as 200 kg.
The gravitational potential energy is given as 39,000 Joule.
The gravitational potential energy at a height ' h' from the surface earth is given as P.E= mass×height×acceleration due to gravity
The value of g=9.8 m/s^2
Hence height [h][tex]=\frac{P.E}{mg}[/tex]
=[tex]\frac{39000}{200*9.8} metre[/tex]
=19.8979 metre
As per the second question we have to calculate the sped and height of the model airplane.
the mass of model airplane is 1 kg
The kinetic energy [K.E] of the airplane is 12.5 joule
we have K.E[tex]=\frac{1}{2} mass*speed^2[/tex]
K.E[tex]=\frac{1}{2}mv^2[/tex]
[tex]v^2=\frac{2K.E }{m}[/tex]
[tex]v^2=\frac{2*12.5}{1}[/tex]
[tex]v=\sqrt{25}[/tex]
v=5 m/s
Again we have to calculate the height [h]
The potential energy is given as 98 Joule.
we know that P.E= mgh
tex]h=\frac{P.E}{mg}[/tex]
=[tex]\frac{98}{1*9.8} metre[/tex]
=10 metre
