A small metal bar whose initial temperature was 20 degrees Celsius is dropped into a large container of boiling water. How long
1 answer:
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Answer:
The answer is "a, c and b"
Explanation:
- Its total block power is equal to the amount of potential energy and kinetic energy.
- Because the original block expansion in all situations will be the same, its potential power in all cases is the same.
- Because the block in the first case has no initial speed, the block has zero film energy.
- For both the second example, it also has the
velocity, but the kinetic energy is higher among the three because its potential and kinetic energy are higher.
- While over the last case the kinetic speed is greater and lower than in the first case, the total energy is also higher than the first lower than that of the second.
- The greater the amplitude was its greater the total energy, therefore lower the second, during the first case the higher the amplitude.
Answer:
c. 1600J
Explanation:
The loss in potential energy of the boy is given by:
where
m = 40 kg is the mass of the boy
g = 9.8 m/s^2 is the acceleration of gravity
is the total change in the height of the boy (4 metres + 2 cm due to the compression of the spring)
Substituting, we find
Answer:
(i) 7.2 feet per minute.
(ii) No, the rate would be different.
(iii) The rate would be always positive.
(iv) the resultant change would be constant.
(v) 0 feet per min
Explanation:
Let the length of ladder is l, x be the height of the top of the ladder from the ground and y be the length of the bottom of the ladder from the wall,
By making the diagram of this situation,
Applying Pythagoras theorem,
Differentiating with respect to t ( time ),
( l = 26 feet = constant )
We have,
(i) From equation (1),
From equation (X),
(ii) From equation (X),
Thus, for different value of x the value of would be different.
(iii) Since, distance = Positive number,
So, the value of y will always a positive number.
Thus, from equation (X),
The rate would always be a positive.
(iv) The length of the ladder is constant, so, the resultant change would be constant.
i.e. x = increases ⇒ y = decreases
y = decreases ⇒ y = increases
(v) if ladder hit the ground x = 0,
So, from equation (X),
