Answer:
The tension on the string is 
Explanation:
From the question we are told that
The mass of the rock is 
The density of the rock is 
Generally the volume of the rock is mathematically evaluated as
substituting values
The volume of the rock immersed in water is
substituting values
mass of water been displaced by the this volume is
According to Archimedes principle
=> 
The weight of the water displace is
The actual weight of the rock is
The tension on the string is
substituting values
Answer:
(a) 
(b) 
Explanation:
Part (a)
The total length of copper cord L=86.3 m
The cross sectional area A=1.71×10⁻⁶m²
The resistivity of copper p=1.72×10⁻⁸Ω
Thus the resistance of extension cord is
Part (b)
The resistance of trimmer Rt=17.9 ohms
When voltage of 120V is applied then the current I is passing through series circuit is
Thus the voltage across the trimmer is:
Answer:
Chemical potential energy is the energy stored in the chemical bonds of a substance. The various chemicals that make up gasoline contain a large amount of chemical potential energy that is released when the gasoline is burned in a controlled way in the engine of the car.
Explanation:
Answer:
a. one-half as great
Explanation:
The power developed by the first lifter is one-half as great as that of the second person.
Power is defined as the rate at which work is done;
Power = 
Since the two lifters do the same work at different time, let us estimate their power;
P₁ = 
P₂ = 
We see that for P₁, power is half of the work done whereas in P₂ power is the same as the work done.
Therefore,
The power of the first weight lifter is one-half the second lifter.
Answer:
B. Maximum velocity of ejected electrons.
Explanation:
The ejection of electrons form a metal surface when the metal surface is exposed to a monochromatic electromagnetic wave of sufficiently short wavelength or higher frequency (or equivalently, above a threshold frequency), which leads to the enough energy of the wave to incident and get absorbed to the exposed surface emits electrons. This phenomenon is known as the photoelectric effect or photo-emission.
The minimum amount of energy required by a metal surface to eject an electron from its surface is called work function of metal surface.
The electrons thus emitted are called photo-electrons.
The current produced as a result is called photo electricity.
Energy of photon is given by:
where:
h = Planck's constant
frequency of the incident radiation.
