Sound level at distance of 15 m is given as 20 dB
so intensity at this distance is given as
now if we move closer to some some distance the sound level is now 50 dB
now the intensity is given as
now we know that
so now the distance from friend must be 47 cm
As we know that power is defined as rate of work done
so we will have
so in order to increase the power as per above formula we know that either we need to increase the work or we need to decrease the time to complete that work
So here the correct answer will be
increase the work being done or decrease the time in which the work is completed.
Answer: D
Neither A nor B
Explanation:
In order to check the clearances for rod and main bearings, you need a set of micrometers and a dial-bore gauge
Measuring the inside diameter of a main or rod bearing will require a dial bore gauge. The best ones to use are accurate down to 0.0001-inch.
So, both technician A and B are incorrect
A motorcycle mainly wastes energy as heat <u>energy</u> and <u>sound</u> energy. In the engine, chemical energy is transformed into mechanical energy. However, the engine is inefficient and much of the chemical energy is lost as heat energy. Also, some of the energy is transformed to sound energy. This explains why the motorcycle is noisy and has an exhaust pipe.
(amount of heat)Q = ? , (Mass) m= 4 g , ΔT = T f - T i = 180 c° - 20 °c = 160 °c ,
Ce = 0.093 cal/g. °c
Q = m C ΔT
Q = 4 g × 0.093 cal/g.c° × ( 180 °c- 20 °c )
Q= 4×0.093 × 160
Q = 59.52 cal
I hope I helped you^_^
