The minimum height h is 65m so that the car will not fall off the track at the top of the circular part of the loop.
<h3>What is mechanical energy?</h3>
Potential energy plus kinetic energy are combined to form mechanical energy. According to the principle of mechanical energy conservation, mechanical energy is constant in an isolated system when only conservative forces are acting on it. Potential energy increases when an object moves in the opposite direction of a conservative net force. Kinetic energy also changes as an object's speed, not velocity, changes. However, nonconservative forces, such as frictional forces, will always be present in real systems; however, if these forces are of minimal magnitude, mechanical energy changes little, making the idea of its conservation a reasonable approximation.
For completing the vertical circle the minimum speed at the bottom must be 
so conserving mechanical energy
⇒ h= 
h = 65m
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Answer:
The approximate combined sound intensity is 
Explanation:
The decibel scale intensity for busy traffic is 80 dB. so intensity will be
, therefore 
In the same way for the loud conversation having a decibel intensity of 70 dB.
, therefore 
Finally we add both of them 
, is the approximate combined sound intensity.
Answer:
first one is b 2nd one is a 3rd is c and the 4th one is c also
Explanation: have a nice day
Theoritically
the body moving with uniform velocity has acceleration zero.
Mathmatically,
u=3m/s
v=3m/s (since body is moving with uniform velocity)
a= v-u/t
3-3/t
0/t
0m/s.s
Answer:
No temperature change occurs from heat transfer if ice melts and becomes liquid water (i.e., during a phase change). For example, consider water dripping from icicles melting on a roof warmed by the Sun. Conversely, water freezes in an ice tray cooled by lower-temperature surroundings.
Explanation:
Energy is required to melt a solid because the cohesive bonds between the molecules in the solid must be broken apart such that, in the liquid, the molecules can move around at comparable kinetic energies; thus, there is no rise in temperature. Similarly, energy is needed to vaporize a liquid, because molecules in a liquid interact with each other via attractive forces. There is no temperature change until a phase change is complete. The temperature of a cup of soda initially at 0ºC stays at 0ºC until all the ice has melted. Conversely, energy is released during freezing and condensation, usually in the form of thermal energy. Work is done by cohesive forces when molecules are brought together. The corresponding energy must be given off (dissipated) to allow them to stay together Figure 2.
The energy involved in a phase change depends on two major factors: the number and strength of bonds or force pairs. The number of bonds is proportional to the number of molecules and thus to the mass of the sample. The strength of forces depends on the type of molecules. The heat Q required to change the phase of a sample of mass m is given by
Q = mLf (melting/freezing,
Q = mLv (vaporization/condensation),
where the latent heat of fusion, Lf, and latent heat of vaporization, Lv, are material constants that are determined experimentally.
