If the light is traveling straight up, then it hits the interface (surface
or boundary) between water and air perpendicularly (90° to the surface).
This direction is the direction of the 'normal' to the surface. So the
angle of incidence is zero, and that means the angle of refraction is
also zero. The light just keeps going in the same direction when it
emerges into the air, and is not bent.
However, its speed increases in air, and that means its wavelength
also becomes longer than it was in the water.
Answer:
Car B has a mass of 800 kg.
General Formulas and Concepts:
<u>Momentum</u>
Law of Conservation of Momentum: 
Explanation:
<u>Step 1: Define</u>
<em>Identify variables</em>
[Given] m₁ = 1200 kg
[Given] v₁i = 10 m/s
[Solve] m₂
[Given] v₂i = 0 m/s
[Given] vf = 6 m/s
<u>Step 2: Solve for m₂</u>
- Substitute in variables [Law of Conservation of Momentum]: (1200 kg)(10 m/s) + m₂(0 m/s) = (1200 kg + m₂)(6 m/s)
- Multiply: 12000 kg · m/s = (1200 kg + m₂)(6 m/s)
- Isolate m₂ term: 2000 kg = 1200 kg + m₂
- Isolate m₂: 800 kg = m₂
Answer: The correct answer is Image B.
Explanation: For an object to accelerate, there should be unbalanced forces present. An object will move in the direction of net force.
Balanced forces are defined as the forces acting on the same object which are equal in magnitude but act in opposite direction. The net forces are 0.
Unbalanced forces are defined as the forces acting on the same object which are unequal in magnitude. The net force is non-zero.
For the given images:
Image A: This box will accelerate easily because the net force is non-zero and is moving in right direction.
Image B: This box will not accelerate because the net force is zero as all the forces are balancing one another. Hence, the object will stay at rest.
Image C: This box will accelerate easily because the net force is non-zero and is acting in between the normal and applied force.
Image D: This box will accelerate easily because the net force is non-zero and is moving in right direction.
Hence, the correct option is Image B.
