Tuesday
June 18, 2013

# Homework Help: Physics

Posted by Carden on Thursday, April 29, 2010 at 5:23pm.

A child sits in a wagon with a pile of 0.60 kg rocks. If she can throw each rock with a speed of 10 m/s relative to the ground, causing the wagon to move, how many rocks must she throw per minute to maintain a constant average speed against a 3.7 N force of friction?

I got .616 rocks/min but that isnt right.

• Physics - drwls, Thursday, April 29, 2010 at 9:03pm

To produce a stady reaction force of 3.7 Newtons, momentum must be thrown out in the opposite direction at a rate dm/dt given by
(dm/dt)*10 m/s = 3.7 N
dm/dt = 0.37 kg/s

That is 0.616 rocks per second, NOT per minute

Related Questions

physics - A wagon is rolling forward on level ground. Friction is negligible. ...
Physics - A wagon is rolling forward on level ground. Friction is negligible. ...
College Physics - A wagon is rolling forward on level ground. Friction is ...
physics - A wagon is rolling forward on level ground. Friction is negligible. ...
physics - A wagon is rolling forward on level ground. Friction is negligible. ...
Physics - A wagon is rolling forward on level ground. Friction is negligible. ...
physics - A small child has a wagon with a mass f 10 kilograms (KG). The child ...
physics - A child wants to throw a rock into a puddle which is 20m away and 20m ...
physics 100 - Bob, who has a mass of 60 , can throw a 800 rock with a speed of ...
Physics - A 32 kg child puts a 15 kg box into a 12 kg wagon. The child then ...