Answer:
the answer is B
Melting point, temperature at which the solid and liquid forms of a pure substance can exist in equilibrium. As heat is applied to a solid, its temperature will increase until the melting point is reached. More heat then will convert the solid into a liquid with no temperature change.
A. IMA: 4
The Ideal Mechanical Advantage (IMA) is given by:

where
is the input distance
is the output distance
For the pulley system in this problem,
and
, so the IMA is

B. MA: 3.59
The actual mechanical advantage (AMA), or simply the Mechanical Advantage (MA), is given by

where
is the output force and
is the input force. For the pulley system in this problem,
and
, so the MA is

C. Efficiency: 89.8 %
The efficiency of a machine is equal to the ratio between the MA and the AMA:

Therefore, in this case,

Answer:
447 K
Explanation:
25 C = 25 + 273 = 298 K
Assuming ideal gas, we can apply the ideal gas law


Since pressure is tripled, then
. Volume is halved, then 

Answer:
8400m
Explanation:
The engine that falls off would have the same constant horizontal velocity as the airplane's when if falls off if we ignore air resistance. So it would have a horizontal velocity of 280m/s for 30seconds before it hits the ground.
Therefor the horizontal distance the engine travels during its fall is
280 * 30 = 8400m
Resistance = (voltage) / (Current)
Resistance = (10 V) / (5 A)
Resistance = 2 ohms.