What is the kinetic energy of a 26 kg eagle flying at an altitude of 65 m at a speed of 19 m/s?
1 answer:
Answer:
4693 J
Explanation:
The kinetic energy of the eagle is given by:
where
m is the mass of the eagle
v is the speed of the eagle
In this problem, m = 26 kg and v = 19 m/s. Substituting into the formula, we find
As we can see, the altitude of the eagle is not relevant for the calculation of the kinetic energy.
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a) 2.64 s
We can solve this part of the problem by using the following SUVAT equation:
where
s is the displacement of the stone
u is the initial velocity
t is the time
a is the acceleration
We must be careful to the signs of s, u and a. Taking upward as positive direction, we have:
- s (displacement) negative, since it is downward: so s = -75.0 m
- u (initial velocity) positive, since it is upward: +15.5 m/s
- a (acceleration) negative, since it is downward: so a= g = -9.8 m/s^2 (acceleration of gravity)
Substituting into the equation,
Solving the equation, we have two solutions: t = -5.80 s and t = 2.84 s. Since the negative solution has no physical meaning, the stone reaches the bottom of the cliff 2.64 s later.
b) 10.4 m/s
The speed of the stone when it reaches the bottom of the cliff can be calculated by using the equation:
where again, we must be careful to the signs of the various quantities:
- u (initial velocity) positive, since it is upward: +15.5 m/s
- a (acceleration) negative, since it is downward: so a = g = -9.8 m/s^2
Substituting t = 2.64 s, we find the final velocity of the stone:
where the negative sign means that the velocity is downward: so the speed is 10.4 m/s.
c) 4.11 s
In this case, we can use again the equation:
where
s is the displacement of the package
u is the initial velocity
t is the time
a is the acceleration
We have:
s = -105 m (vertical displacement of the package, downward so negative)
u = +5.40 m/s (initial velocity of the package, which is the same as the helicopter, upward so positive)
a = g = -9.8 m/s^2
Substituting into the equation,
Which gives two solutions: t = -5.21 s and t = 4.11 s. Again, we discard the first solution since it is negative, so the package reaches the ground after
t = 4.11 seconds.
Answer:
copper will have more change in temperature as compare with aluminum
Explanation:
Hot piece of copper is made in contact with cold piece of aluminium
So here thermal energy transfer will take place from copper to aluminium
so by energy conservation we can say that heat given by copper is same as the heat absorbed by aluminium.
now we have
here we know that
= specific heat capacity of copper
= specific heat capacity of aluminum
given that specific heat capacity of aluminium is more than double that of copper
so we can say
so here if the mass of copper and aluminium is same then
so temperature change of copper is twice the temperature change of aluminium
So copper will have more change in temperature as compare with aluminum