Hi there!
Assuming you're asking about the solar system, there are nine planets. But, if you're wanting to know about the universe, there are trillions and trillions of planets (most of which we haven't yet discovered).
Hope this helps!
to your question is 54 cm
By conservation of momentum,
Distance lighter fragment slide= 7*6.7=46.9m
i recommend Biography of Malala Yousafzai
I have learned her biography
that really motivated me
