Answer: False but read why
Heated water molecules expands ( become less dense) but they do float to the top.
Answer:
Q = C M T where C is the specific, M the mass, T the temperature change
Note 1 cal = 4.19 Joules
1562.75 J / (4.19 J/cal) = 378 cal
C = Q / (M * T) = 378 cal / (25.35 g * 155 deg C)
C = .096 cal / g deg C
Before going to answer this question first we have to know the fundamental principle of magnetism.
A magnet have two poles .The important characteristic of a magnet is that like poles will repel each other while unlike poles will attract each other.
Through this concept the question can be answered as explained below-
A-As per first option the side of magnet A is repelled by the south pole of magnet B. Hence the pole of a must be south .It can't be north as it will lead to attraction.
B-The side of magnet A is repelled by the north pole of magnet B. Hence the side of A must be north pole.It can't be a south pole.
C-The side of magnet A is attracted by the south pole of magnet B .Hence the side of magnet A must be north.Hence this is right
D-The side of magnet A is attracted by the north pole of magnet B. Hence the side of A must south.It can't be north as it will lead to repulsion.
Hence the option C is right.
To develop this problem it is necessary to apply the concepts related to Wavelength, The relationship between speed, voltage and linear density as well as frequency. By definition the speed as a function of the tension and the linear density is given by
Where,
T = Tension
Linear density
Our data are given by
Tension , T = 70 N
Linear density , 
Amplitude , A = 7 cm = 0.07 m
Period , t = 0.35 s
Replacing our values,
Speed can also be expressed as
Re-arrange to find \lambda
Where,
f = Frequency,
Which is also described in function of the Period as,
Therefore replacing to find 
Therefore the wavelength of the waves created in the string is 3.49m
Answer:
c.
Explanation:
We are given that
Acceleration due to gravity on the moon=
Acceleration due to gravity on the earth=
Net force due to am on an object on moon=
There is no friction and no drag force and there is no gravity involved
Then, the force acting on an object on earth=
(given)
Hence, option c is true.
