Froghoppers may be the insect jumping champs. these 6-mm-long bugs can spring 70 cm into the air, about the same distance as the flea. but the froghopper is 60 times more massive than a flea, at 12mg. the froghopper pushes off for about 4mm.
part a: what average force does it exert on the surface?
part b: compare this to the gravitational force that earth exerts on the big.
a) this is about 176 times less than the weight of the froghopper. b) this is about 176 times the weight of the froghopper. c) this is equal the weight of the froghopper.

Suppose a diode consists of a cylindrical cathode with a radius of 6.200×10^−2 cm , mounted coaxially within a cylindrical anode with a radius of 0.5580 cm . the potential difference between the anode and cathode is 260 v . an electron leaves the surface of the cathode with zero initial speed (v initial=0). find its speed vfinal when it strikes the anode.

When the displacement of a mass on a spring is 12a the half of the amplitude, what fraction of the mechanical energy is kinetic energy? at what displacement, as a fraction of a, is the mechanical energy half kinetic and half potential?

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kpa and 17°c. this system uses a regenerator as well as reheating and intercooling – the intercooler returns the air to the inlet temperature. the pressure ratio across each compressor is 4 ; 300 kj/kg of heat are added to the air in each combustion chamber; and the regenerator operates perfectly while increasing the temperature of the cold air by 20°c. determine the system’s thermal efficiency. assume isentropic operations for all compressor and the turbine stages and use constant specific heats at room temperature. (0.378)