Answer:
The boat's acceleration is 4 m/s²
Explanation:
This question seeks to test the knowledge of acceleration and how to calculate acceleration when the speed is provided. Hence, the formula for acceleration would be used here.
Acceleration (m/s²) = speed (in m/s) ÷ time (in seconds)
Acceleration = 80 m/s ÷ 20 secs
Acceleration = 4 m/s² or 4 ms⁻²
The boat's acceleration is 4 m/s²
Explanation:
Archimedes' principle states that the upward buoyant force which is exerted on body when immersed whether fully submerged or partially in the fluid is equal to weight of fluid which body displaces and this force acts in upward direction at center of mass of displaced fluid.
Thus,
<u>Weight of the displaced fluid = Weight of the object - Weight of object in fluid.</u>
Answer:
The length of the wire is 83.2 m.
Explanation:
Given that,
Power of heater, P = 300 W
Voltage, V = 110 V
The resistivity of nichrome wire is, 
The electric power of a wire is given by :

Area of cross section of the wire is :

Resistance of a material is given by :

So, the length of the wire is 83.2 m. Hence, this is the required solution.
Answer:
B. Geosphere
A. Biosphere
A. Atmosphere
Explanation:
Volcanic eruptions occurs within the Geosphere. The geosphere is the rock solid earth make up of rocks that extends into the deep interior.
Magma formed deep within the crust rises to elevated parts and finally erupts as lava on the surface. When they cool, they solidify to form volcanic rocks.
The volcanic eruptions affects the biosphere significantly. The biosphere is the portion of the earth where all life forms exists.
Gases and ash spewed during an eruption into the atmosphere causes severe changes to weather and leads to pollution. The atmosphere is the gaseous envelope round the earth.