I think the correct answer from the choices listed above is option B. When calculating the power bill, power companies use kilowatt-hours. This unit is a derived unit of energy equal to 3.6 MJ. If energy is being transmitted or used at a constant rate (power) over a period of time, the total energy in kilowatt-hours is the product of the power in kilowatts and the time.
Answer: The given statement is false.
Explanation:
According to Newton's third law of motion, every action has an equal and opposite reaction. So, when we apply force in one direction on an object then the object also applies a force in the opposite direction.
Hence, it is true that two forces in each pair of forces act in opposite directions.
For example, when we push a wooden box of 20 kg in the forward direction then the box will also apply a force in the opposite direction.
But the statement two forces in each pair can either both act on the same body or they can act on different bodies is false.
Answer:
Explanation:
Volume of lead object = volume of aluminium object = V
mass of lead object > mass of aluminium object
When both the objects immersed in water, the buoyant force acting on both the objects.
Buoyant force = Volume immersed x density of water x gravity
As the volume of both the objects is same, so the buoyant force acting on both the objects is same.
So, weight in air of lead object is more than the weight in air of aluminium object.
Answer:
Speed of 0.08 kg mass when it will reach to the bottom position is 1.94 m/s
Explanation:
When rod is released from rest then due to unbalanced torque about the hinge the system will rotate
Now moment of inertia of the system is given as
now we have
now we have
so we have
now by energy conservation we can say work done by gravity must be equal to change in kinetic energy
so we have
Now speed of 0.08 kg mass when it reaches to bottom point is given as
