B
because it will pick it up while coming down not just flowing on low land<span />
Answer:
<h2>1. Friction is A. a force</h2>
<h2>2. An unbalanced force is B. When the object moves and accelerates</h2>
Answer:
Because the light reflects multiple times until it gets to the Cassegrain focus.
Explanation:
The Cassegrain design can be seen in a reflecting telescope. In this type of design the light is collected by a concave mirror, and then intercepted by a secondary convex mirror, and sends it down to a central opening in the primary mirror (concave mirror), in which a detector is placed (Cassegrain focus)
Since, the light is reflected many times due to Cassegrain design, that leads to shorter telescopes.
Mechanical energy = potential energy + kinetic energy
The ball is on the ground so it has no potential energy. that's all i know.