Work Done = Force x distance
Since she exerted a horizontal force of 20N over a distance of 5m, the work done is 20N x 5m which is equals to 100 joules
The net force on the sledge is 31.64N.
Frictional force = µkR
= 0.269 x 42.2 x 9.81 = 111.36
net force = 143N - 111.36N
= 31.64N
refer brainly.com/question/24557767
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The 'Rite of Spring' was composed by Igor Stravinsky.
Answer:
h f = W + KE
Input energy equals work function plus KE of emitted electron
W = 6.63E-34 * 2.5E15 - 6.3 * 1.6E-19
W = 6.63 * 2.5 * 10^-19 - 10.1 * E-19 ev (1ev = 1.6E-19 J)
W = (16.6 - 10.1)E-19 = 6.5E-19 J
h f = 6.5E-19 J for electrons to be emitted with zero KE
f = 6.5E-19 / 6.63E-34 = .98E-15 / sec = 9.8E-14 / sec (threshold)