Answer:
If the acceleration of an object remains constant, then its velocity is constant. False
If the acceleration of an object moving along a line is always 0, then its velocity is constant. True
It is impossible for the instantaneous velocity at all times aless than or equalstless than or equalsb to equal the average velocity over the interval aless than or equalstless than or equalsb. True
A moving object can have negative acceleration and increasing speed. False
Explanation:
First of all, before we can talk of acceleration, then there must be a change in velocity. If the velocity of a body is constant, then there will not be any acceleration at all.
If the acceleration is zero, then there is no change in velocity, the velocity is constant.
The instantaneous velocity is always changing all through the motion hence it cannot be determined at all times to equal the average velocity.
If the acceleration is negative, it simply means that the velocity is decreasing with time. Hence there can't be a negative acceleration and increasing velocity.
Answer:
D. The ice-to-liquid phase change of water requires less energy than the liquid-to-vapor phase.
Explanation:
In the phase change from liquid to gas, the bonds between atoms are completely broken. The phase change from liquid to gas requires more energy because the bonds must be completely broken for it to take place, rather than just loosened as in the phase change of solid to liquid.
Phase changes can have a strong stabilizing effect on temperatures that are not near the melting and boiling points, since evaporation and condensation occur even at temperatures below the boiling point.
More energy is required to evaporate water below the boiling point than at the boiling point, because the kinetic energy of water molecules at temperatures below 100°C is less than that at 100°C, so less energy is available from random thermal motions.
There is a relationship between the energy of a photon and its wavelength. This can be expressed as a mathematical equation shown below:
E = hc/λ
where
h is the Planck's constant equal to 6.62607004 × 10⁻³⁴ m²<span> kg / s
c is the speed of light equal to 3</span>× 10⁸ m/s
λ is the wavelength
3.5×10⁻¹⁶ J = (6.62607004 × 10⁻³⁴ m² kg / s)(3× 10⁸ m/s)/λ
Solving for λ,
λ = 56.8×10⁻⁹ m or<em> 56.8 nm</em>
