Potential energy is defined by formula

here
m = mass
g = acceleration due to gravity
h = height
Now here two different stones are located at same height
while mass of stone A is twice that of stone B
so here we can say potential energy of A is

Similarly potential energy of B is

now if we take the ratio of two energy

so we can say potential energy of stone A is two times the potential energy of B
Answer:
all above
Explanation:
friction is necessary to live
The answer is ultra violet radiation. From the air
Answer:
Selenium is a semiconductor
Explanation:
Selenium is a semiconductor.
Elements in the column IV and VI of the periodic table are referred to as Semiconductor.
Selenium lies in the column VI along with Tellurium
Some other elements of the column IV are silicon, germanium, and tin
Answer:
Explanation:
The net force on the potatoes is given by:
F= 52 - mgSintheta
F= 52- (2×9.8× Sin70°)
F = 52 -18.4
F= 33.58N
Using Newton's 2nd law
F = ma
a=F/m = 33.58/ 2 = 16.79m/s^2
Using the equation of motion:
V^2= u^2 + 2as
V^2 = 0 + 2× 16.79 x2
V^2 = 67.16
V=sqrt(68.16)
V= 8.195m/s This is the exit velocity of the potatoes
Kinetic energy, K.E = 1/2mv^2
KE= 1/2 × 2 × 8.195^2
KE = 67.16J