Answer:
Acceleration due to gravity is 20
So option (E) will be correct answer
Explanation:
We have given length of the pendulum l = 2 m
Time period of the pendulum T = 2 sec
We have to find acceleration due to gravity g
We know that time period of pendulum is given by



Squaring both side


So acceleration due to gravity is 20
So option (E) will be correct answer.
The correct answer would be True!
Answer:
Simple machine: pair of tongs, seesaw and wheelbarrow
Compound machine: sewing machine, fishing rod and reel and crane.
Explanation:
Simple machine is the simplest device to use mechanical advantages. It has simplest mechanism to multiply the magnitude of force.
So, pair of tongs, seesaw and wheelbarrow are the example of simple machine because their mechanism is simplest.
Compound machine is a device that is made up of more than one simple machine.
so, sewing machine, fishing rod and reel and crane are example of compound machine because these devices shows more than one machine in it.
Thus, classification is as follows:
Simple machine: pair of tongs, seesaw and wheelbarrow
Compound machine: sewing machine, fishing rod and reel and crane.
The first law of thermodynamics can be written as

where

is the variation of internal energy of the system

is the amount of heat absorbed by the system

is the work done by the system on the surrounding.
Using this form, the sign convention for Q and W becomes:
Q > 0 --> heat absorbed by the system (because it increases the internal energy)
Q < 0 --> heat released by the system (because it decreases the internal energy)
W > 0 --> work done by the system (for instance, an expansion: when the system expands, it does work on the surrounding, and so the internal energy decreases, this is why there is a negative sign in the formula Q-W)
W < 0 --> work done by the surrounding on the system (for instance, a compression: when the system is compressed, the surrounding is doing work on the system, and so the internal energy of the system increases)