Item 8 Part A A crate on a motorized cart starts from rest and moves with a cons

Question

Item 8 Part A A crate on a motorized cart starts from rest and moves with a constant eastward acceleration of a 2.30 m/s2.A worker assists the cart by pushing on the crate with a force that is eastward and has magnitude that depends on time according to F(t) = (5.40 N/st what is the instantaneous power supplied by this force at t = 4.40 s ? Express your answer to three significant figures and include the appropriate units. P- 282 Submit My Answers Give Up Incorrect, One attempt remaining; Try Again

Explanation / Answer

The instantaneous power is the instantaneous rate of doing work.

Consider at time t, a small time increment dT and that the elemental work done is F(t)*dS,

where, dS is the incremental distance moved by the force.

In the limit as dT tends to zero:

Rate of work = F(t)*dS/dT

= F(t)*V(t)

V(t) = u+at

= 0+2.3*t

Rate of work = F(t)*V(t)

= 5.4*t*2.3*t

=12.42 t^2

At t = 4.4 s;

P(t) = 12.42 t^2

= 12.42*4.4^2

= 240 W

ANSWER

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