Answer:
horizontal structural member that supports a floor. Beams are typically wood, cold formed metal framing or steel.
Joists
Horizontal timbers, beams or bars supporting a floor.
Answer:
42.96 km/s
Explanation:
From the conservation of Energy

Mass gets cancelled

= Escape velocity of Earth = 11.2 km/s
= Velocity of projectile = 44.4 km/s

The velocity of the spacecraft when it is more than halfway to the star is 42.96 km/s
Answer:
Distance traveled will be 5.6307 m
Explanation:
Time t = 3 sec
We have given force F = 25 N
We know that force is given by F = ma
So ma = 25 -----------eqn 1
Weight is given by W = 196 N
We know that weight is given by W = mg
So mg = 196 -----------------eqn 2
From equation 1 and equation 2 

Initial velocity is given as 0 so u = 0 m/sec
From second equation of motion 