(1) The potential energy at the top of the ball’s motion is 18 J.
(3) The kinetic energy increases as the potential energy decreases.
(4) The kinetic energy decreases as the potential energy increases.
(5) The total mechanical energy of the ball stays constant.
Explanation:
The total mechanical energy of the ball is equal to the sum of its kinetic energy (K, energy due to the motion) and its potential energy (U, energy due to the height of the ball). Mathematically:
In absence of friction, the mechanical energy of the ball is conserved, so in this case, it is always equal to 18 J. Let's now use this information to analyze each of the given statements:
(1) The potential energy at the top of the ball’s motion is 18 J. --> TRUE. In fact, at the top, the ball's speed becomes zero, so its kinetic energy is zero: K = 0. This means that all the mechanical energy of the ball is potential energy, therefore
E = U = 18 J
(2) The kinetic energy is less when the ball is thrown than when it is caught. --> FALSE. As we said, in absence of friction, the mechanical energy is conserved, therefore it always remains equal to 18 J.
(3) The kinetic energy increases as the potential energy decreases. --> TRUE. As we said, the sum of potential+kinetic energy remains constant:
E = K + U = 18 J
therefore, when the potential energy decreases, the kinetic energy increases.
(4)The kinetic energy decreases as the potential energy increases. --> TRUE. For the same reason described in (3).
(5)The total mechanical energy of the ball stays constant. --> TRUE. As we said at the beginning, the total mechanical energy is constant.
(6) The mechanical energy decreases as the ball moves up and increases as the ball comes down. --> FALSE. As we said, the mechanical energy remains constant, so it cannot change.
Learn more about kinetic and potential energy:
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Answer:
Explanation:
a.
AIM :
TO STUDY HOW VELOCITY OF WAVES ON THE STRING DEPENDS ON THE STRING'S TENSION.
APPARATUS:
Oscillator, long strings , some masses( to create tension in string) and the support ( rectangular wooden piece).
EXPERIMENTAL SETUP:
1. Measure the length of the string and mass of the weights used.
2. Connect one end of string to the oscillator.
3. Place the support below string on table such that the string is in same line without touching table.
4. After the support, the string should hang freely.
5. The other end of string is connected with some small measured masses which should be hanging.
PROCEDURE:
1. Note down the length of string and mass of weights.
2. Adjust the frequency in the oscillator which creates standing waves in the string.
3. Start from lower frequency and note down the lowest frequency at which mild sound is heard or when string forms one loop while oscillating.
4. Calculate the wavelength using of waves using length of string.
5. Calculate the velocity using frequency and wavelength.
6. Calculate linear mass density.
8. Repeat the procedure with different masses.
7. plot a graph with tension in y axis and linear mass density in x axis.
8. Find slope and compare with velocity.
Linear mass density
µ = m/l(kg-1)
tension
T = m x 9.8N
wave length
ƛ = 2L
b.
We can analyze the data by comparing slope of the graph, tension Vs linear mass density with velocity which is constant for constant length.
Write the slope value in terms of value of velocity and find the relationship between velocity and string's tension.
The expected result is
slope = v²
T ∝ V²
