The frequency, f, of a wave is the number of waves passing a point in a certain time. We normally use a time of one second, so this gives frequency the unit hertz (Hz), since one hertz is equal to one wave per second.
Answer:
T = 20.84°C
Explanation:
From the law of conservation of energy:
Heat Lost by Copper Block = Heat Gained by Aluminum Calorimeter + Heat Gained by Water

where,
= mass of copper = 227 g
= mass of water = 844 g
= mass of aluminum = 155 g
= specific heat capacity of calorimeter = 385 J/kg.°C
= specific heat capacity of water = 4200 J/kg.°C
= specific heat capacity of aluminum = 890 J/kg.°C
= change in temperature of copper = 283°C - T
= change in temperature of water = T - 14.6°C
= change in temperature of aluminum = T - 14.6°C
T = equilibrium temperature = ?
Therefore,

<u>T = 20.84°C</u>
Answer:D
Explanation:
Given
mass of object 
Distance traveled 
velocity acquired 
conserving Energy at the moment when object start falling and when it gains 12 m/s velocity
Initial Energy
Final Energy

where
is friction work if any


Since Friction is Present therefore it is a case of Open system and net external Force is zero
An open system is a system where exchange of energy and mass is allowed and Friction is acting on the object shows that system is Open .
Mechanical and Chemical. (Weathering and erosion)
Answer:
14cm
Explanation:
Mass per gram of the piece of wire;
2g of the wire is found in 1m
Since
100cm = 1m;
So;
100cm of the wire contains 2g of the wire
To provide 0.28g
Since;
2g of wire is made up of 100cm
0.28g of wire will be contained in
= 14cm
14cm of the wire will contain 0.28g