Saturday
December 20, 2014

Homework Help: physics

Posted by VitaX on Saturday, October 16, 2010 at 9:17pm.

A 0.720 kg snowball is fired from a cliff 8.10 m high. The snowball's initial velocity is 14.2 m/s, directed 30.0 above the horizontal. (a) How much work is done on the snowball by the gravitational force during its flight to the flat ground below the cliff? (b) What is the change in the gravitational potential energy of the snowball-Earth system during the flight? (c) If that gravitational potential energy is taken to be zero at the height of the cliff, what is its value when the snowball reaches the ground?

I think I understand each problem. But I'll post what I think I need to do then someone can confirm if its right or not.

a)mgyi - mgyf = Wg I get 57 J

b)Change in Gravitational Potential Energy is just the negative of that work so its -57 J

c)The answer should just be zero since it was zero at the top of the cliff.

I'm skeptical because I didn't use the angle or velocity given. That's why I'm not sure if these answers are right or not. Do I use W = change in kinetic energy for part a or no?

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

physics - A 1.5 kg snowball is fired from a cliff 12.5m high with an inital ...
Physics - A 1.50 kg snowball is fired from a cliff 13.0 m high with an initial ...
Physics/Math - A 1.50 kg snowball is fired from a cliff 12.5 m high with an ...
Physics/Math - A 1.50 kg snowball is fired from a cliff 13.5 m high with an ...
physics - One strategy in a snowball fight is to throw a snowball at a high ...
physics - One strategy in a snowball fight is to throw a snowball at a ...
physics - Snowballs are thrown with a speed of 12.5 m/s from a roof 7.8 m above ...
physics - You and a friend stand on a snow-covered roof. You both throw ...
Physics - A child throws a snowball with a horizontal velocity of 18m/s directly...
Physics - a 65-kg ice skater moving to the right with a velocity of 2.50m/s ...

Search
Members