Most asteroids are small 4. They would hit the Moon first 5. The Earth's gravity would slingshot them. Some meteors are too small to be detected in space , but are large enough to cause mass damage in space. For example the crater in Arizona.
Asteroids coming strainght on to earth are more dangerous than grazing the Earth's surface.
They can create massive tsunamis. The dust off comet tails would freeze life on Earth. Ateroids the size of 1 km would wipe out life in the proximinty the size of a Hiroshoma Bomb. If an asteroid were to hit the moon in would create mass destruction on earth 7. If impact from the asteroid sends shockwaves to the planet than whatever the impact do not devastate the shockwave would.