Question

(a) Taking the potential energy to be zero at infinite separation, find the potential energy of...

(a) Taking the potential energy to be zero at infinite separation, find the potential energy of a 30 kg object at the surface of the Earth. (Use 6.37 ✕ 106 m for the Earth's radius.)
________________J

(b) Find the potential energy of the same object at a height above the Earth's surface equal to the Earth's radius.
_______________J

(c) Find the escape speed for a body projected from this height.
__________________km/s

0 0
Add a comment Improve this question Transcribed image text
Answer #1

a)

Here is the formula for Gravitational Potential Energy

Ug = -GMm/r

Ug = - GMm/(R+h)

We plug given values,

Ug = - [(6.67*10^-11*5.9*10^24*30)/(6.37*10^6+ 0)

Calculating,

Ug = -1.85*10^9 J

b)

Now here h=R

Ug = - GMm/(R+h)

Ug = - [(6.67*10^-11*5.9*10^24*30)/(6.37*10^6+ 6.37*10^6)

Calculating,

Ug = -9.27*10^8 J

c)

To determine the escape velocity from this distance we just recall the usual method setting KE + PE = 0

1/2mv^2 = GMm/r

1/2,mv^2 = 9.27*10^8

1/2*30*v^2 = 9.27*10^8  

v= 7.8*10^3 m/s = 7.8km/s

Add a comment
Know the answer?
Add Answer to:
(a) Taking the potential energy to be zero at infinite separation, find the potential energy of...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions
ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT