A weight lifter lifts an 800 N bar a distance of 3 m is just 3.5 seconds. What is the power output of the lifter in watts?

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Answer 1 · 2018-04-10T14:53:28

257.14 W

First you need to find out the work done by him:
Work = Force x Displacement

Given: Force = #300N# and Displacement= #3m#
Use this in the formula above:
Work = #300N xx 3m # = #900Nm#

Now, use the work done you have found to find out the power output:
Power = Work ÷ Time taken
Power = #900Nm ÷ 3.5s# = #257.14 W#

Answer 2 · 2018-04-10T14:56:54

Approximately #685.7# watts.

We first find the work done by the weightlifter. Work is expressed through the equation,

#W=F*d#

#F# is the force in newtons

#d# is the distance moved in meters

And so, we get, #W=800 \ "N"*3 \ "m"=2400 \ "J"#.

Power is measured through the equation,

#P=W/t#

#W# is the work done in joules

#t# is the time in seconds

Plugging in the values we found, we get,

#P=(2400 \ "J")/(3.5 \ "s")#

#~~685.7 \ "W"#