<em>Quantities that determine the kinetic energy of a body are its </em><em>mass and velocity </em>
Answer: <em>mass and velocity </em>
Explanation:
The kinetic energy of a body is the energy possessed by an object by virtue of its motion. It is given by the equation
Where m represents mass of the body and v represents its velocity.
Two bodies of equal velocity but different mass the heavier body will have greater kinetic energy. When an object is at rest its velocity is equal to zero. Thus its kinetic energy will be zero. Hence it can be concluded that only moving bodies have kinetic energy.
Stationary objects placed at a height possess potential energy which is the energy by virtue of their position or configuration. The total mechanical energy of a system is the sum of potential and kinetic energy.
Total distance: 56 meters. Magnitude and direction of displacement: 20 meters South.
Explanation:
The term distance refers to space between one point and other, or the total space a body or object covered while moving. In the case presented, this can be calculated by adding the partial distances given. This means the total distance is 56 meters as 26 meters + 18 meters + 12 meters = 56 meters.
On the other hand, displacement considers the distance from the initial position to the final position, and the direction of movement. This means partial distances should not be added but each movement should be considered according to the direction. The process is shown below:
-The first movement was 26 meters southward; this means by the end of this movement the distance between the initial position was 26 meters south.
- The second movement was 18 northward; this means the kayaker moved 18 meters towards the position. This changes the displacement to 8 meters South as 26 meters south - 18 meters north = 8 meters to the South.
-The last movement was 12 meters sound; this means the kayaker increased the distance from the original position 8 meters to the South + 12 meters to the South = 20 meters South (total displacement.)
Answer:
The answer to the question is
The distance d, which locates the point where the light strikes the bottom is 29.345 m from the spotlight.
Explanation:
To solve the question we note that Snell's law states that
The product of the incident index and the sine of the angle of incident is equal to the product of the refractive index and the sine of the angle of refraction
n₁sinθ₁ = n₂sinθ₂
y = 2.2 m and strikes at x = 8.5 m, therefore tanθ₁ = 2.2/8.5 = 0.259 and
θ₁ = 14.511 °
n₁ = 1.0003 = refractive index of air
n₂ = 1.33 = refractive index of water
Therefore sinθ₂ = 
= 
= 0.1885 and θ₂ = 10.86 °
Since the water depth is 4.0 m we have tanθ₂ = 
or x₂ = 
=
= 20.845 m
d = x₂ + 8.5 = 20.845 m + 8.5 m = 29.345 m.
Answer:
<em>d. The sail should be reflective because in this case the momentum transferred to the sail per unit area per unit time is larger than for absorbing sail, therefore the radiation pressure is larger for the reflective sail.</em>
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Explanation:
Let us take the momentum of a photon unit as u
we know that the rate of change of momentum is proportional to the force exerted.
For a absorbing surface, the photon is absorbed, therefore the final momentum is zero. From this we can say that
F = (u - 0)/t = u/t
for a unit time, the force is proportional to the momentum of the wave due to its energy density. Therefore,
F = u
For a reflecting surface, the momentum of the wave strikes the sail and changes direction. Since we know that the speed of light does not change, then the force is proportional to
F = (u - (-u))/t = 2u/t
just as the we did above, it becomes
F = 2u.
From this we can see that the force for a reflective sail is twice of that for an absorbing sail, and we know that the pressure is proportional to the force for a given area. From these, we conclude that <em>the sail should be reflective because in this case the momentum transferred to the sail per unit area per unit time is larger than for absorbing sail, therefore the radiation pressure is larger for the reflective sail.</em>
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