Answer:
b) It is impossible to tell without knowing the masses.
Explanation:
The temperature change of a substance when it receives/gives off a certain amount of heat Q is given by
where
Q is the amount of heat
m is the mass of the substance
Cs is the specific heat capacity of the substance
In this case, we have a hot piece of aluminum in contact with a cold piece of copper: the amount of heat given off by the aluminum is equal to the amount of heat absorbed by the copper, so Q is the same for the two substances. However, we see that the temperature change of the two substances depends on two other factors: the mass, m, and the specific heat, Cs. So, since we know only the specific heat of the two substances, but not their mass, we can't tell which object will experience the greater temperature change.
There could be a little bit of conduction through the air that's between the soup and your hand. But it's very small, because air is not a good conductor of heat.
It's mostly <em>convection</em> ... hot air and steam rising from the soup to your hand.
Then, of course, there HAS to be some conduction when the hot gases reach your hand ... their heat has to soak into your skin, and that's conduction.
Answer:
The decelerating force is 
Solution:
As per the question:
Frontal Area, A = 
Speed of the spaceship, v = 
Mass density of dust, 
Now, to calculate the average decelerating force exerted by the particle:
(1)
Volume, 
Thus substituting the value of volume, V in eqn (1):
where
A = Area
v = velocity
t = time
(2)
From Newton's second law of motion:
Thus differentiating w.r.t time 't':
where
= average decelerating force of the particle
Now, substituting suitable values in the above eqn:
Answer:
Energy needed = 1100 kJ
Explanation:
Energy needed = Change in kinetic energy
Initial velocity = 15 m/s
Mass, m = 1600 kg
Final velocity = 40 m/s
Energy needed = Change in kinetic energy = 1280000-180000 = 1100000J
Energy needed = 1100 kJ
