Answer:
The answer is A
Explanation:
When a rockets thrusters push on the ground the ground pushes back on the rocket with equal force in the opposite direction. Hence the rocket takes off.
Newtons third law of motion states, for every action there is an equal and opposite reaction.
Answer: B. meteorites, UV rays
The earth's atmosphere plays an important role in shielding the space rocks and meteorites enters inside the earth due to collision with the celestial body. Due to high heat and pressure in the mesospheric layer of the atmosphere these meteorites burned up before reaching the biosphere or hydrosphere system of the earth. The UV rays are protected from entering into the earth atmosphere by the ozone layer present in the stratosphere of the atmosphere. Both meteorites and UV rays can negatively effect the human population. Therefore, the atmosphere is an agent which provides protection against them.
a) An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. <u>This is because a positive and negative electric charge is produced, therefore the balloon sticks to the wall.</u>
b) When an object is thrown up, it comes back to ground <u>because of gravitational attraction force of earth</u>.
c) Mountaineers suffer nose bleeding at higher altitudes <u>because the oxygen level decreases with increase in altitude, which the body cannot adjust.</u>
d) Foundations of high rise buildings are kept wide <u>because more is the area of contact, less is the pressure efforts. So, foundations are wide so as to decrease the possibility of the building from falling down.</u>
e) Deep sea divers or high altitude fliers wear special suits <u>so as prevent their body from being crushed by the water pressure. Since water pressure is maximum at deep seas and oceans, therefore, more is the risk of being injured.</u>
f) Walls of a dam are thickened near the base <u>so that the dam can handle the kinetic energy pressure and prevent itself from breaking down, which if not, can lead to flooding</u>.
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Answer:
The total number of significant figures is twelve.
Explanation:
Answer with Explanation:
We are given that
Weight of an ore sample=17.5 N
Tension in the cord=11.2 N
We have to find the total volume and the density of the sample.
We know that
Tension, T=
=buoyancy force
T=Tension force
W=Weight
By using the formula
N
Where
=Volume of object
=Density of water
=Acceleration due to gravity
Substitute the values then we get
Volume of sample=
Density of sample,
Where mass of ore sample=1.79 kg
Substitute the values then, we get
Density of the sample=