Answer:
The needed energy to melt of ice is 1670 J.
Explanation:
Given that,
Mass of ice = 5 g
Specific latent heat = 334000 J/kg
We need to calculate the energy
Using formula of energy

Where, m = mass
L = latent heat
Put the value into the formula


Hence, The needed energy to melt of ice is 1670 J.
Answer:
So the ratio will be 
Explanation:
We have given heat engine absorbs 450 joule from high temperature reservoir
So 
As the heat engine expels 290 j
So work done W = 290 J
We know that efficiency 
It is given that efficiency of the engine only 55 % of Carnot engine
So efficiency of Carnot engine 
Efficiency of Carnot engine is 


No, it will only melt if the temperature is lowered. If you compress it, it will change the shape, but it will not change the state it is in (i.e. solid).
Answer:
Explanation:
The greatest speed is attained at middle point or equilibrium point or where displacement from equilibrium point is zero .
When the object remains at one of the extreme point it experiences greatest acceleration but at that point velocity is zero . Due to acceleration , its velocity goes on increasing till it come to equilibrium point . At this point acceleration becomes zero . After that its velocity starts decreasing because of negative acceleration . Hence at middle point velocity is maximum .
The greatest acceleration is attained at maximum displacement or at one of the two extreme end .
Greatest restoring force too will be at position where acceleration is maximum because acceleration is produced by restoring force .
Restoring force is proportional to displacement or extension against restoring force . So it will be maximum when displacement is maximum .
Zero restoring force exists at equilibrium position or middle point or at point where displacement is zero . It is so because acceleration at that point is zero .
Answer:

Explanation:
Given:
mass of person, 
mass of merry go-round, 
radius of merry go-round, 
velocity of the person running, 
<u>We consider merry go-round as a ring:</u>
Now the moment of inertial of the ring is given as,



<u>Moment of inertia of the person considering as a point mass:</u>



<u>Now according to the conservation of angular momentum:</u>

where:
angular velocity of the merry-go-round
angular velocity of the person running


