Answer:
Mechanical waves need matter to transfer energy while electromagnetic waves do not. ... Waves change direction when they move from one material into another (matter) through the process of refraction. The wave will change direction when the speed of the wave changes.
As you know, plants are usually green<span>, which means that most other colors are absorbed. One of the most common pigments is called chlorophyll, and one of the varieties is responsible for the </span>green<span> color of plants; it strongly absorbs </span>blue<span> and </span>red<span>light, which leaves only the </span>green<span> light to make it to our eyes.</span>
Answer : The temperature when the water and pan reach thermal equilibrium short time later is, 
Explanation :
In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.


where,
= specific heat of aluminium = 
= specific heat of water = 
= mass of aluminum = 0.500 kg = 500 g
= mass of water = 0.250 kg = 250 g
= final temperature of mixture = ?
= initial temperature of aluminum = 
= initial temperature of water = 
Now put all the given values in the above formula, we get:


Therefore, the temperature when the water and pan reach thermal equilibrium short time later is, 
Answer:
The length of line is 78 cm or 0.78 m.
Explanation:
initial reading 2 mark
final reading 80 cm
The length of the line
= final reading - initial reading
= 80 - 2
= 78 cm
1 cm = 0.01 m
So, 78 cm = 0.78 m
1. Answer: components
A two dimensional vector can be divided into two parts called horizontal component and vertical component.
A three dimensional vector can be divided into three components: one along x-axis, one along y-axis and one along z-axis.
Hence, the vector parts that add up to the resultant are called components.
2. Answer: 5 miles.
The resultant distance along the straight line from the starting point to the end point would be the displacement.
The displacement would be equal to the magnitude of the hypotenuse formed in the right triangle.
Displacement, 
3. Answer: Scalar
A scalar quantity has only magnitude. For example, speed and distance are scalar quantities and can be normally added to find the total.
A vector quantity has both magnitude as well as direction. The components are summed according to vector addition rules. For example, velocity, acceleration, force etc.