Answer:
C. D.C.
Explanation:
The current that is being described here is D.C. or direct current. It is the D.C. that moves in one direction from negative to positive. May be created by a battery. It is different from the A.C.( alternating current whose polarity changes regularly). It is A.C. that is used in electrical outlets and not D.C.So, the current option is C.
The picture isn’t clear so I can’t read the dimensions of the box but I can try my best to guide u through the question.
For part a u need to find the volume of the box as that will equal the volume of sand that can be filled inside.
For this u multiply the height, width and length of the box.
For part b the mass of sand alone will be
=Mass of box + sand - Mass of empty box
=216 - 40
=176 grams
For part c the density of sand can be calculated by the formula
Density= Mass/Volume
So the mass (176g) / volume from part a
For part d u need to know that something will float if it has a lower density than what it is floating in. If the final density of sand that was found in part c is less than the density of gold (19.3 g/cm^3) it will float. Otherwise it will sink.
Hope this helped!
Answer:
p = -8 kg-m/s
Explanation:
Given that,
Initial speed of the rock, u = 8 m/s
Mass of the rock, m = 1 kg
The ball travels up to a maximum height, then returns to the ground.
We need to find the rock's momentum as it strikes the ground. Let v be the final speed of the rock. Its final speed is as same as initial speed i.e. 8 m/s but in negative direction. So
p = mv
p = 1 kg × (-8 m/s)
= -8 kg-m/s
So, the rock's momentum as it strikes the ground is (-8 kg-m/s).
Nuclear energy is EXTREMELY ecofriendly, punching down any fossil fuels and even wind energy. It also is reliable, and has low emissions. However, nuclear energy is somewhat expensive and can go wrong, being dangerous to the environment and people. Along with this, uranium is finite and radioactive waste disposal is really bad.
