Here's one of my questions:(adsbygoogle = window.adsbygoogle || []).push({});

Workers load a 506 kg safe onto an elevator that lifts it 95 m to the twentieth floor of an office building. How much work did the elevator do on the safe?

Now, to solve this, can't i just use the formula W=F(parallel) * delta S. So that would be W=506kg*9.81m/s (since F=ma) *95m= 471086 J

am i correct here?

My other question has me confused

The shot used by male shot-putters has a mass of 7.26 kg. During a throw a shot is initially swun around in a circle reaching a speed of about 3.5 m/s. It is then accelerated, more or less, in a straight line over a distance of about 1.7 m, leaving the hand at roughly 14 m/s.

(a) How much kinetic energy does the shot initally get in the turning phase?

(b) How much kinetic energy does it pickup in the straight-line portion of the launch?

(c) What's the average force exerted on the shot during this latter part of the launch?

Now i get (a) and (b) i just used the equation KE=1/2mv^2, and came up with 44.47J and 711.48J respectively, but I don't quite see how I am supposed to come up with the average force exerted on the shot in the latter part of the launch.

(alot of what i'm looking for here is just confirmation that i am on the right track, i've been missing to many homework problems and it's destroying my grade)

For my last question i attatched a picture, its of a ball rolling down a circularly curved track. The question is what do the speed, acceleration and kinetic energy do as it rolls down the track?

speed-increases

acceleration-increases

and kinetic energy- increases as well. Am i right in this way of thinking?

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# Homework Help: Energy and Work Done

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