Answer:

Explanation:
The motion of ballistic pendulum is modelled by the appropriate use of the Principle of Energy Conservation:

The final velocity of the system formed by the ballistic pendulum and the bullet is:



Initial velocity of the bullet can be calculated from the expression derived of the Principle of Momentum:


One of the concepts to be used to solve this problem is that of thermal efficiency, that is, that coefficient or dimensionless ratio calculated as the ratio of the energy produced and the energy supplied to the machine.
From the temperature the value is given as

Where,
T_L = Cold focus temperature
T_H = Hot spot temperature
Our values are given as,
T_L = 20\° C = (20+273) K = 293 K
T_H = 440\° C = (440+273) K = 713 K
Replacing we have,



Therefore the maximum possible efficiency the car can have is 58.9%
Answer:
(a) 
(b) 
(c) K.E. = 21.168 J
(d) 
Explanation:
Given:
- mass of a block, M = 3.6 kg
- initial velocity of the block,

- constant downward acceleration,

That a constant upward acceleration of
is applied in the presence of gravity.
∴
- height through which the block falls, d = 4.2 m
(a)
Force by the cord on the block,



∴Work by the cord on the block,


We take -ve sign because the direction of force and the displacement are opposite to each other.

(b)
Force on the block due to gravity:

∵the gravity is naturally a constant and we cannot change it


∴Work by the gravity on the block,



(c)
Kinetic energy of the block will be equal to the net work done i.e. sum of the two works.
mathematically:


K.E. = 21.168 J
(d)
From the equation of motion:

putting the respective values:

is the speed when the block has fallen 4.2 meters.
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