Action and reaction are the rocket fuel going backwards and the rocket going forward. 3
f=ma 2
the rocket was at rest, 1, until there was a resultant external force 1 at which point 2 came in, with 3 alongside
Force = (mass) x (acceleration)
= (0.75 kg) x (25 m/s²)
= (0.75 x 25) kg-m/s²
= 18.75 newtons .
Note that even though we're talking about a 'hit', the acceleration only
lasts as long as the bat is in contact with the ball. Once the ball leaves
the bat, it travels at whatever speed it had at the instant when they parted.
Any change in its speed or direction after that is the result of gravity, air
resistance, and the fielder's mitt. I learned a lot about these things a few
weeks ago, since I live in Chicago, about 6 miles from Wrigley Field, in
a house full of Cubs fans.
<span>Mass of rock 1 is m1 = 10 kg Mass of rock 2 is m2 = 20 kg 10-kg rock takes T (the same time ) to reach the ground as similar to 20-kg rock that takes time T to reach the ground. If no air resistance is present, the rate of descent depends only on how far the object has fallen, no matter how heavy the object is. This means that two objects will reach the ground at the same time if they are dropped simultaneously from the same height. This statement follows from the law of conservation of energy and has been demonstrated experimentally by dropping a feather and a lead ball in an airless tube.
When air resistance plays a role, the shape of the object becomes important. THUS 10-KG & 20-KG ROCK reaches the ground in T-time</span>