A child sits in a wagon with a pile of 0.59 kg rocks. If she can throw each rock with a speed of 10 m/s relative to the ground, how many rocks must she throw per minute to maintain a constant average speed against a 2.8 N force of friction?(adsbygoogle = window.adsbygoogle || []).push({});

I know this question is probably increadibly easy...its listed as an easy problem in the book...but it is not clicking.

I believe I have to use the thrust = (delta m/delta t) x v but I think I am setting it up wrong.

I had 2.8 as the thrust as this is the amount of force needed to keep an average speed so

2.8 = (0.59/x) x 10

which leads to 5.9/2.8

which equals 2.1 seconds in time....

If this first part is correct, then i am having trouble converting this time into amount of rocks.

I suspect I set the first part up wrong though

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Super Easy Question Im Sure

**Physics Forums | Science Articles, Homework Help, Discussion**