physics(URGENT!!!!!)
posted by Anonimus .
A meteorite of mass m= 2 ×104 kg is approaching headon a planet of mass M= 7 ×1029 kg and radius R= 5 ×104 km. Assume that the meteorite is initially at a very large distance from the planet where it has a speed v0= 5 ×102 km/s. Take G= 6.67 ×10−11.
Determine the speed of the meteorite v (in m/s) just before it hits the surface of the planet. (The planet has no atmosphere, so we can neglect all friction before impact)
v=

Intiial PE=GMm/r
Initial KE=1/2 m v^2
can you convert that intial energy to final ke? 
my final formula is: Vf=sqrt(Vi^2+(mMG/r))
r being the radius of the planet 
1/2 m vf^2=1/2 m vi^2+GMm/r
where r is the initial distance of the object. You can ignore the final PE, as the object is very far from the planet initiually. That does not lead to what you got. 
but isn't the object initially at r=infinity therefore P_i=0 and the potential energy just before impact Mmg/the radius of the planet? or am i completely of target

1/2 m vf^2=1/2 m vi^2+GMm/r  it's correct!
Respond to this Question
Similar Questions

physics
An object rests on the surface of planet y. Its mass is unknown. Find the acceleration due to gravity near the surface of planet y. Answer in m/s/s. G=6.673x10^23 radius of planet y=2439700m mass of planet y=3.302x10^23kg radius of … 
Physics
Two small aluminum spheres, each having mass 2.65×10−2 , are separated by 85.0 . How many electrons would have to be removed from one sphere and added to the other to cause an attractive force between the spheres of magnitude … 
physics (help)
A meteorite of mass m= 1 ×104 kg is approaching headon a planet of mass M= 3 ×1029 kg and radius R= 7 ×104 km. Assume that the meteorite is initially at a very large distance from the planet where it has a speed v0= 2 ×102 km/s. … 
PHYSICS(HELP)
A meteorite of mass m= 2×10^4 kg is approaching headon a planet of mass M= 4×10^29 kg and radius R= 2×10^4 km. Assume that the meteorite is initially at a very large distance from the planet where it has a speed v0= 5×10^2 km/s. … 
Physics(IMPORTANT)
A meteorite of mass 1*10^4kg is approaching headon a planet of mass 5*10^29kg and radius 5*10^4km. Assume that the meteorite is initially at a very large distance from the planet where it has a speed 3*10^2km/s. Take 6.67*10^11. … 
Physics plz help .
A meteorite of mass m= 2 ×10^4 kg is approaching headon a planet of mass M= 6 ×10^29 kg and radius R= 8 ×10^4 km. Assume that the meteorite is initially at a very large distance from the planet where it has a speed v0= 7 ×10^2 … 
physics(URGENT!!!!!)
A spherical nonrotating planet (with no atmosphere) has mass m1= 5 ×1024 kg and radius r1= 7000 km. A projectile of mass m2≪m1 is fired from the surface of the planet at a point A with a speed vA at an angle α=30∘ … 
Math
For questions 1 and 2 choose the equation or proportion that you can use to solve the problem: What number is 73% of 215? 
math
for questions 1 and 2 chose the equation or proportion that you can use to solve the problem what number is 73% of 215 A( 215=0.73n B( n=0.73 X 215 C( 0.73=n X 215 D( 215=73n what percent of 94 is 23 A( n/94=23/100 B( 23/94=n/100 C( … 
physics
. If planet Elijah has a mass of 6.0 x 106 kg and a radius of 4.0 x 104 km. What would be the force on the surface of the planet?