Answer:
The correct option is 'd': The change in shape of an object.
Explanation:
Since by definition physical change is defined as a change that changes only the form of an object or substance and producing no change in the chemical composition of the substance. Physical changes are reversible in nature.
As we can see from all the options the change in the shape of the object is a reversible change as we can always remold any substance in any shape, thus it confirms to a physical change.
The change in the molecular composition of an object is a hallmark of a chemical reaction thus indicates a chemical change.
The smell change in an object is an indication of a chemical change in the object hence is not a physical change.
Answer:
This is because the speed of a wave is determined by the medium through which it is passing. When light speeds up as it passes from one material to another, the angle of refraction is bigger than the angle of incidence. For example, this happens when light passes from water to air or from glass to water ❤
Answer:
2406 miles
Explanation:
Let A be the starting position, B the junction position and C the final position after flying the 3.5 hrs. Also, let b be the distance from the starting point:
#Distance traveled in 1.5hrs is;
#Distance traveled in next two hrs:
#Now using the Cosine Rule:
Hence, the pilot is 2406 miles from her starting position.
Answer:
A. when the mass has a displacement of zero
Explanation:
The velocity of a mass on a spring can be calculated by using the law of conservation of energy. In fact, the total energy of the mass-spring system is equal to the sum of the elastic potential energy (U) of the spring and the kinetic energy (K) of the mass:
where
k is the spring constant
x is the displacement of the mass with respect to the equilibrium position of the spring
m is the mass
v is the velocity of the mass
Since the total energy E must remain constant, we can notice the following:
- When the displacement is zero (x=0), the velocity must be maximum, because U=0 so K is maximum
- When the displacement is maximum, the velocity must be minimum (zero), because U is maximum and K=0
Based on these observations, we can conclude that the velocity of the mass is at its maximum value when the displacement is zero, so the correct option is A.
Answer:
The male gamete is smaller in comparison to that of the female gamete.
The male gamete is conical from the front while the female gamete is spherical.
The cytoplasm in the male gamete is less in comparison to that of the female gamete.
The male gamete can move with the help of the tail while the female gametes are immobile and do not have any tail or flagella present.
The number of mitochondria present in the sperm is less than the number of mitochondria present in the ovum.
The male gamete has acrosome present in the head region that contains enzymes for dissolving the membranes present around the ovum. The ovum does not contain such digestive enzymes.
Explanation:
