A man accelerates a crate across a rough, level floor with an efficiency of 50%. Which is true? Group of answer choices

Energy is not conserved, because the efficiency is less than 100%.

Part of the man’s work goes into the kinetic energy of the crate, while the other part of his work is done against friction.

The energy gained by the crate equals the work done by the man.

The work done by the man equals the distance the crate moves multiplied by the friction.

Afaulty model rocket moves in the xy-plane (the positive y direction is vertically upward). the rocket's acceleration has components ax(t) = ? t2 and ay(t) = ? ? ? t, where ? = 2.50 m/s4 , ? = 9.00 m/s2 , and ? = 1.40 m/s3 . at t = 0 the rocket is at the origin and has velocity ~v0 = v0x ? i + v0y ? j with v0x = 1.00 m/s and v0y = 7.00 m/s. (a) calculate the velocity and position vectors as functions of time. (b) what is the maximum height reached by the rocket? (c) sketch the path of the rocket. (d) what is the horizontal displacement of the rocket when it returns to y = 0?

Aforce of 40n applied at the end of length 4m and diameter 2.00mm process and extension of 0.24mm,calculate the stress on the wire, strain in the wire and the young modulus for the material of the wire

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