Answer:
2726.54 J/K
Explanation:
Entropy change =
where
m = mass of water = 450g = 0.45kg
= 2.26 MJ/kg = 2260000 J/kg
T = temperature at which water change from liquid to steam = 100 degree Celsius = 272 + 100 = 373 degree kelvin.
Entropy change = = 2726.54 J/K
1) 2 Forces
2) 563 N, upward
3) , upward
4) Speed is decreasing
Explanation:
1)
There are two forces acting on teacher during his skydiving:
- The force of gravity (also known as weight), acting downward (towards the Earth's centre), of magnitude
where
m is the mass of the teacher
g is the acceleration due to gravity
- The air resistance, of magnitude R = 1200 N, acting upward (air resistance always acts in the direction opposite to the direction of motion)
There are no other forces, therefore the correct answer is:
2 Forces
2)
The net force on the system is given by the vector resultant of the two forces described in part 1). Since the two forces act along the same line but in opposite directions, the net force will be equal to the difference between the two forces, so:
where we have chosen downward as positive direction, and where
m = 65 kg is the mass of the teacher
is the acceleration due to gravity
R = 1200 N is the air drag
Therefore, the net force on the teacher is
And the negative sign means that the direction of the net force is upward.
3)
The acceleration of the system can be found by using Newton's second law of motion, which can be written as
where
a is the acceleration
is the net force
m is the mass of the teacher
Here we have
m = 65 kg
Therefore, the acceleration is
And the negative sign indicates that the direction of the acceleration is opposite to the motion (so, upward).
4)
From part 3), we observed that:
- The motion of the teacher is downward (he is moving downward)
- However, the direction of his acceleration is upward
This means that the velocity and the acceleration of the system have opposite directions.
As we know, the velocity of an accelerating system can be written as
where
v is the velocity after time t
u is the initial velocity
a is the acceleration
Since a is negative, we see that , so
: this means that the velocity of the teacher is decreasing with time, so, the teacher is slowing down, and therefore his speed is decreasing.
Answer:21.18 m
Explanation:
Given
initial speed u=10 m/s
height of building h=22 m
time taken to complete 22 m
initial vertical velocity =0
Horizontal Distance moved