Answer:
4. Parabola
Explanation:
The motion of the flight of the grenade is a projectile motion, it's shape is best illustrated using a parabolic diagram.
It's not a circle as the path is not totally round.
It's not an ellipse as the path of motion is not a a completely bounded shape.
Its not a hyperbola as a hyperbola is an open curve with two branches.
Its a parabolic shape because a parabola has just one branch
When a cloud of gas and dust in space was disturbed, maybe by the explosion of a nearby star.This explosion made waves in space which squeezed the cloud of gas & dust.
Answer:

Explanation:
We must use conservation of linear momentum before and after the collision, 
Before the collision we have:

where these are the masses are initial velocities of both players.
After the collision we have:

since they clong together, acting as one body.
This means we have:

Or:

Which for our values is:

Its called static friction.