In the first law, an object will not change its motion unless a force acts on it. So I think the answer is A. Only objects that are moving.
Answer:
0.24
Explanation:
Mass of ball= 12g=0.012Kg
height of ball= 2.5m
velocity of ball before falling= 3.2m/s
potential energy of the ball=mgh= 0.012*10*2.5=0.3J
kinetic energy of the ball=0.5*m
=0.5*0.012*3.2*3.2=0.6J
Loss in mechanical energy during the fall= potential energy- Kinetic energy= 0.3-0.06=0.24J
note: During the fall, the potential energy of the ball is converted to kinetic energy. the loss in energy is due to air resistance.
Answer:
The work input during this process is -742 kJ
Explanation:
Given;
Initial temperature of nitrogen T₁ = 250 K
final temperature of nitrogen T₂ = 450 K
mass of nitrogen, m = 5 kg

The work input during the process is calculated as;

where;
R is gas constant = 0.2968 kJ/kgK
substitute given values in above equation.

Therefore, the work input during this process is -742 kJ