Gravitational potential energy increase

[majormuss]

Homework Statement

A person weighing 6.0 × 102 Newtons rides an
elevator upward at an average speed of 3.0 meters
per second for 5.0 seconds. How much does this
person’s gravitational potential energy increase
as a result of this ride?
(1) 3.6 × 102 J (3) 3.0 × 103 J
(2) 1.8 × 103 J (4) 9.0 × 103 J

Homework Equations

PE=mgh, KE=1/2mx^2

The Attempt at a Solution

I tried solving the question this way but it seems am wrong... mgh=1/2mx^2 and I arrived at number '3'. Need help!

 

[Gear300]

U = mgh ... that is about all you'll need (you know m and g, you just need to solve for the displacement).

 

[majormuss]

U = mgh ... that is about all you'll need (you know m and g, you just need to solve for the displacement).

wat is U?

 

[majormuss]

wat is U?

 

[Wellesley]

wat is U?

Potential Energy=mass*g*height

I tried solving the question this way but it seems am wrong... mgh=1/2mx^2 and I arrived at number '3'. Need help!

Your approach can't be used in this type of problem. If you wanted to find the speed of a car at the bottom of a hill, you can set the two equations equal to each other (PE for the top, KE, for the bottom).

A person weighing 6.0 × 102 Newtons rides an
elevator upward at an average speed of 3.0 meters
per second for 5.0 seconds.

Try finding the three parts of the equation Gear300 posted...you just need to solve for height (or displacement).

 

[majormuss]

thanx a bunch, just realized my blunder...