Answer:
yes, 800 has 1 significant digit
neither leading zero nor trelling zero are significant figure except when there's a decimal point
Answer:
8.56 m/s2
Explanation:
Using law of energy conservation while taking into account of the rotational and translation kinetic energy, when the solid cylinder rolls down the incline we have the potential energy converted to kinetic energy:


where m is the mass,
is the moments of inertia of the solid cylinder
is the angular speed of the cylinder



So if you plot a liner chart of h vs
and get a slope of 6.42 then that means 3/(4g) = 6.42 so 
The gravitational acceleration on this planet is 8.56 m/s2
Answer:
15 is the answer
Explanation:
i multiplied 1.5 by 10 to get 15