A crane lifts a 450 kg concrete to the top of a 50 m building in 5 s. Assuming g= 10 m/s
)
2
a) The potential energy of the concrete.
, calculate;
b) The power developed by the crane

Idon’t quite understand this problem

Based on the concept of the wave-like nature of light, huygens' theory of light postulates that the more light was "bent" by a substance the slower it would move while traversing across that substance. a) deflection b) interference c) refraction d) resonance

Which is the correct symbol for an isotope of iodine with 53 protons and 78 neutrons?