Answer: Option D: It must be in the solid state to be used.
A material that is used to provide energy is for work is known as fuel. For practical use, it is important that the fuel must occur in abundance or can be easily produced. It should be made of elements that can easily combine with oxygen. This is required for burning. It must produce large amount of energy. So, it must contain large amount of stored energy. It is useful only when a small quantity can produce large amount of energy. It can be in any state, solid liquid or gas.
Therefore, it is not important that it must be in the solid state to be used.
Explanation:
It is given that,
Force on grindstone, F = 180 N
Radius of grindstone, r = 0.28 m
Mass of grindstone, m = 75 kg
We need to find the angular acceleration of the grindstone. In rotational motion, the relation between the torque and angular acceleration is given by :


I is the moment of inertia of solid disk, 
is the torque exerted, 




So, the angular acceleration of the disk is
. Hence, this is the required solution.
Answer:
A planet's mass has no effect on its orbit around the Sun.
Explanation:
The kepler's third law tells us:

where
is the orbit period and
is the semi-major axis.
As we can see from the equation, the period depends only on the measure of the semi-major axis
of the orbit, that is, how far a planet is from the sun.
The equation tells us that the closer a planet is to the sun, the faster it will go around it.
The mass does not appear in the equation to calculate the period.
This is why it is concluded from the third law of Kepler that<u> the period, or the orbit of a planet around the sun, does not depend on its mass.</u>
the answer i: A planet's mass has no effect on its orbit around the Sun.
Answer:
the answer is B it is right
Explanation:
Answer:
1.5 times
Explanation:
= depth of the diver initially = 5 m
= density of seawater = 1030 kg m⁻³
= Initial pressure at the depth
= final pressure after rising = 101325 Pa
Initial pressure at the depth is given as

= Initial volume at the depth
= Final volume after rising
Since the temperature remains constant, we have
