1. (C.) -Si- is silicone which at room temp is a solid and it's a hard crystalline Brittle rock basically...
2. And it will Be D. NOT C... i can't stand user's who throw out answers for free points....
The correct answers would be B, and d
Answer:-683 cal
Explanation:
Given
Heat released by system Q=-255 cal
as heat released is taken as negative and vice-versa
Work done by system W=428 cal
From First law of thermodynamics
=change in internal Energy

Answer:
1470 W
Explanation:
Power: This can be defined as the rate at which work is done or energy is used up. The S.I unit of power is Watt (W).
The expression for power is given as,
P = Energy/time
P = mgh/t ...................... Equation 1
Where P = power, m = mass, h = height, t = time, g = acceleration due to gravity.
Given: m = 75 kg, g =9.8 m/s², h = 1 m, t = 1 s.
Substitute into equation 1
P = (75×1×9.8)/1
P = 735 W.
From the above,
1 hp = 735 W
2 hp = (2×735) W
2 hp = 1470 W.
Hence 2 hp = 1470 W
Answer:
421.83 m.
Explanation:
The following data were obtained from the question:
Height (h) = 396.9 m
Initial velocity (u) = 46.87 m/s
Horizontal distance (s) =...?
First, we shall determine the time taken for the ball to get to the ground.
This can be calculated by doing the following:
t = √(2h/g)
Acceleration due to gravity (g) = 9.8 m/s²
Height (h) = 396.9 m
Time (t) =.?
t = √(2h/g)
t = √(2 x 396.9 / 9.8)
t = √81
t = 9 secs.
Therefore, it took 9 secs fir the ball to get to the ground.
Finally, we shall determine the horizontal distance travelled by the ball as illustrated below:
Time (t) = 9 secs.
Initial velocity (u) = 46.87 m/s
Horizontal distance (s) =...?
s = ut
s = 46.87 x 9
s = 421.83 m
Therefore, the horizontal distance travelled by the ball is 421.83 m