Cars are the mechanical device which convert chemical energy of fuel into mechanical energy, the engine used in the automobiles car are very inefficient, they can only convert 30-40% of chemical energy of fuel into mechanical energy, since thermodynamics is the branch of science that deals with the conversion of energy, thus due to poor conversion rate of chemical energy into mechanical energy, cars are known as inefficient machine.
Choices 'C' and 'D' are both correct.
(Except in 'C', changing the temperature from 1°C to 3°C is not usually
described as 'cooling', and it's not the water's 'mass' that changes. But
water does contract in volume during that change.)
Answer
given,
length of bar = 80 cm
mass of the bar = 10 kg
smaller mass = 4 kg
distance = 20 cm
taking moment about B
difference between two scale = 8 - 6
= 2 N
If it;s a good insulator, there'll be no heat transfer warm to cold. So, over time, given the insulation ... nothing should happen ...
