Starting
from rest, a 1.8x10-4 kg flea springs straight
upward. While the flea is pushing off from the ground, the ground
exerts an average upward force of 0.41 N on it. This force does
3.6x10-4 J of work on the
flea. (a) What is the flea's speed
when it leaves the ground? (b) How far upward does the
flea move while it is pushing off? Ignore both air resistance and
the flea's weight.
a) The work don on the flea will be converted to its kinetic energy = 0.5* m *v^2 = 3.6*10^4
v = 2 m/s
b) all the energy gained will be converted to its potential energy
m*g*H = 3.6 * 10^-4
H = 0.204 m = 20.4 cm
Starting from rest, a 1.8x10-4 kg flea springs straight upward. While the flea is pushing off...
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Starting from rest, a 1.5x10-4 kg flea springs straight upward. While the flea is pushing off from the ground, the ground exerts an average upward force of 0.36 N on it. This force does 3.7x10-4 J of work on the flea. (a) What is the flea's speed when it leaves the ground? (b) How far upward does the flea move while it is pushing off? Ignore both air resistance and the flea's weight. (a) Number Units (b) Number Units
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A 65.5 kg person jumps from rest off a 2.83 m-high tower straight down into the water. Neglect air resistance during the descent. She comes to rest 1.15 m under the surface of the water. Determine the magnitude of the average force that the water exerts on the diver. This force is nonconservative.
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