Question

8) If two masses are m, and m2, distance is 'd',and constant of gravitation is ‘G’, then gravitational force for attraction will be
9) How can we distinguish one sound from another having the same pitch and loudness?
10) What is the audible range of frequency for human beings?
11) What is the function of middle ear?
12) What us ultrasonic and infrasonic sound waves?
13) What is SONAR?
14) Define average speed.
15) A bus travels a distance of 120 km with a speed of 40 km/h and returns with a speed of 30
km/h. Calculate the average speed for the entire journey.
16 What does the odometer of an automobile measure? Which of the following is moving faster?
Justify your answer.
(i) A scooter moving with a speed of 300 m per minute.
(ii) A car moving with a speed of 36 km per hour.
17) A bus accelerates uniformly from 54 km/h to 72 km/h in 10 seconds Calculate
(i) acceleration in m/s?
(ii) distance covered by the bus in metres during this interval.
18) A car moves with a speed of 30 km/h ‘for half an hour, 25 km/h for one hour and 40 km/h
for two hours. Calculate the average speed of the car.
19) A certain household has consumed 250 units of energy during a month How much energy is this in joules?
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Answer 1

Answer:

13) sonar is used in ship used to measure the depth of the sea

12) ultra sonic sound

ultra sonic sound are the whose frequency above 20000hz

infra sonic

infra sonic are those frequency below 20hz

10) aduabile range of frequency is 20hz to 20000hz