National Aeronautics and Space Administration University of Maryland Ball Aerospace & Technologies Corp. Jet Propulsion Laboratory California Institute of Technology Credits & Awards Contact Us Privacy Statement
spacer image
spacer
UMD ASTRONOMY spacer STUDENT INFO spacer UMD OBSERVATORY spacer PDS-SBN spacer BIMA
spacer
Deep Impact
Deep Impact
Home Search Sitemap Frequently Asked Questions Contact Us spacer
Deep Impact Mission Science Technology Mission Results Gallery Education Discovery Zone Your Community Press Discovery Zone - Mission Challenge

See National Math and Science Standards for this Challenge.


In order to reduce costs, the Mission Team decided to go with a slightly smaller launch rocket. That meant that they had to reduce the overall mass of the flight system. One of the places where they were able to reduce mass was on the impactor. The mass of the impactor was changed from 500kg to 350 kg. The scientists were concerned though because this means that the amount of energy produced at impact will be reduced as well. Help us figure out how much energy is produced at impact with the 350 kg impactor!

Update: In the spring of 2002, the mass of the impactor was increased from 350kg to 370 kg. How will the extra 20 kilos affect the amount of energy produced?

Hints:
Mass of the impactor: m = 370 kg
Velocity of the impactor: v = 10.2 km/s


What do we know? From the website, we know:
Mass of the impactor: m = 370 kg
Velocity of the impactor: v = 10.2 km/s

What formula should we use? That's a bit tougher since it's not in the website. It helps to know a little bit of physics, but we'll help!

Formula to use: kinetic energy = 1/2 (mv2)

Plugging in the numbers
KE= 1/2 (370kg (10.2 km/s)2 )
= 19247.4 kg·km2/s2

But in the website the answer says 19 Gigajoules. If we look up Joules, we find that 1 J = 1 kg·m2/s2 (meters not km) so we need to go back and convert the velocity from km/s to m/s and we get v = 10200 m/s.

Plugging in the numbers again
KE= 1/2 (370kg (10200 m/s)2 )
= 1.92 × 1010 kg·m2/s2 or 1.92 × 1010 J
1 GJ = 109 J
therefore, KE = 19 GJ

But how much is 19 GJ? Well, it turns out that 1 Megaton of TNT (or 1 million tons of TNT) is equivalent to 4 × 1015 J.

Some more converting:

19 GJ = 19 × 109 J × (1 × 106 tons TNT/4 × 1015 J)
the joules cancel, 109 × 106/1015 cancels leaving

= 19/4 tons of TNT
= 4.8 tons of TNT

More Challenges



redbar-bottom
spacer
spacer spacer spacer spacer spacer spacer
spacer FirstGov - Your First Click to the U.S. Government   spacer
Web Curator: Maura Rountree-Brown
Webmaster: Elizabeth Warner
Last Updated: Wednesday June 14, 2017
Clearance No. CL 01-0944
spacer spacer spacer spacer spacer spacer