Answer:
a. If an object's speed is constant, then its acceleration must be zero.
FALSE
As we know that acceleration is defined as the rate of change in velocity

so we can not say anything about the acceleration when speed is given to as and no information is given about velocity
b. If an object's acceleration is zero, then its speed must be constant.
TRUE
As we know that acceleration is defined as the rate of change in velocity

Since we know that if acceleration is 0 then velocity must be constant and hence speed is also constant
c. If an object's velocity is constant, then its speed must be constant.
TRUE
Since velocity is constant then it shows that its magnitude and direction both are constant so its speed is also constant.
d. If an object's acceleration is zero, its velocity must be constant.
TRUE
As we know that acceleration is defined as the rate of change in velocity

Since we know that if acceleration is 0 then velocity must be constant
e. If an object's speed is constant, then its velocity must be constant.
FALSE
Speed is just the magnitude so we can not say about its direction and hence if speed is constant then velocity may or may not change
Answer: *The inner planet that has two moons is Mars * the only planet in the Solar System with clockwise rotation is Venus * The surface of Mercury is covered with ancient magma ( which is similar to the spews of volcanoes on Earth as well) * The planet that is closest to Earth is Mercury * Venus has more volcanoes than any other planet * Earth's moon formed when a(n) can sometimes be called the Big Splash or can be called the Theia impact (Luna the moon formed from the ejecta of the collision between the Proto- Earth and Mars sized planet) * Mars is called the red planet because it's soil contains the element iron oxide ( which is the compound that gives blood and rust hue)
Explanation: Hope this helped :)
8.1) Here, Pressure increases with depth in the ocean at higher rate then that of increase in altitude in atmosphere. So, the rate of change of pressure is different in these journeys.So, your most correct answer would be option D.
8.2) Difference in the shape of lines is due to different density of air & water. So, that physical property and your answer would be option A
So, in Short Answers of your questions are:
8.1) - Option D
8.2) - Option A
Hope this helps!
86.4×10^6 joule is energy does one house use during each 24 hr day.
20 MJ of light energy
Consumption of electricity is 1 kW.
The energy consumption lasts for 24 hours.
energy=power×time
energy=10^3×24×3600
energy=86.4×10^6 joule
Energy in physics is the ability to perform work. Different shapes, such as potential, kinetic, thermal, electrical, chemical, radioactive, etc., may be assumed by it. Other examples of energy being transferred from one body to another include heat and work. Energy is always distributed after it has been transported in accordance with its type. Thus, heat transfer could result in thermal energy, whereas work could result in mechanical energy.
Motion is a trait shared by all forms of energy. For instance, if a body is moving, it has kinetic energy. Due to the object's design, which incorporates potential energy, a tensioned object, like a spring or bow, has the ability to move even when at rest.
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