Solving a Rainforest Biologist's Homework Problem

[sweedeljoseph]

Homework Statement

A rain forest biologist is pulling a 50 kg crate of bananas at a constant rate from the ground to the canopy with a rope on a pulley. The distance that the crate has to go is 80 m. When the crate has traveled 40 m, a monkey with a mass of 50 kg jumps on to the top of the crate, and rides on the crate the rest of the way up.
a) How much work does the biologist do on the crate?
b) How much potential energy does the crate have at the top of the tree?

Homework Equations

Wgrav=mg(h_o-h_i)
PEgrav=mgh

The Attempt at a Solution

i remember doing something like this in class before. but there was more than just this. i forgot how to do it though. are you supposed to do it twice then add or something. because another thing is added. like for work you have the normal then when the monkey on it its more. would you just add those together? for the potential energy for the mass you would add both the monkey and the crate? and for the height you would just use the full? you wouldn't use the middle when the monkey jumped on because it wants it at the top right?

thank you!
sweedeljoseph

 

[tiny-tim]

A rain forest biologist is pulling a 50 kg crate of bananas at a constant rate from the ground to the canopy with a rope on a pulley. The distance that the crate has to go is 80 m. When the crate has traveled 40 m, a monkey with a mass of 50 kg jumps on to the top of the crate, and rides on the crate the rest of the way up.
a) How much work does the biologist do on the crate

Hi sweedeljoseph!

Just use the work-energy theorem …

work done = change in energy.