The picture shows “regular reflection”
Explanation:
Law of conservation of momentum states that in an isolated system when two objects collide with each other then total momentum before and after the collision is equal.
Thus, we can conclude that the law of conservation of momentum states that the total momentum of interacting objects does not change. This means the total momentum before a collision or explosion is equal to the to momentum after a collision or explosion.
Efficiency η of a Carnot engine is defined to be:
<span>η = 1 - Tc / Th = (Th - Tc) / Th </span>
<span>where </span>
<span>Tc is the absolute temperature of the cold reservoir, and </span>
<span>Th is the absolute temperature of the hot reservoir. </span>
<span>In this case, given is η=22% and Th - Tc = 75K </span>
<span>Notice that although temperature difference is given in °C it has same numerical value in Kelvins because magnitude of the degree Celsius is exactly equal to that of the Kelvin (the difference between two scales is only in their starting points). </span>
<span>Th = (Th - Tc) / η </span>
<span>Th = 75 / 0.22 = 341 K (rounded to closest number) </span>
<span>Tc = Th - 75 = 266 K </span>
<span>Lower temperature is Tc = 266 K </span>
<span>Higher temperature is Th = 341 K</span>
Answer:
The net force on the skater is zero. (
)
Explanation:
According to Newton's First Law, an object is at equilibrium when either it is at rest or moves at constant velocity, which means a net force of zero. Based on the given statement, there are no external forces acting on skate and, therefore, the net force on the skater is zero. ()
Answer:
, downward
Explanation:
There is only one force acting on the ball during its motion: the force of gravity, which is given by
where
m is the mass of the ball
is the acceleration of gravity (downward)
According to Newton's second law,
where F is the net force on the object and a is its acceleration. Rearranging for a,
As we said, the only force acting on the ball is gravity, so F = mg and the acceleration of the ball is:
Therefore, the ball has a constant acceleration of downward for the entire motion.
