Answer:

Given:
Mass of the polar bear (m) = 6.8 kg
Speed of the polar bear (v) = 5.0 m/s
To Find:
Kinetic energy of the polar bear (KE)
Explanation:
Formula:

Substituting values of m & v in the equation:





Kinetic energy of the polar bear (KE) = 23002.1 J
Incomplete question. Missing part:
"it took him 10 seconds to move the couch. What was his power?"
Answer:
50 W
Explanation:
The power developed is given by:

where
W is the work done
t is the time taken
In this problem,
W = 500 J
t = 10.0 s
Substituting into the equation, we find

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Below is the solution:
<span>centripetal accel = 1.5*g
ω²r = 1.5*9.8m/s²
ω² * 8m = 14.7 m/s²
ω = 1.36 rad/s * 1rev/2πrads * 60s/min = 12.9 rpm</span>
The estimation of the age of the Earth comes from scientists who studied the rock formation under the Earth's crust. They believe that during the Big Bang, the Earth, together with the other celestial bodies in the universe, were formed. Under the Earth's soil contain radioactive materials that have known decay rates. Using these rate, they undergo tests like rock dating to find the time of its existence.