Answer:
the earthe would fly off into space in a straight line
Answer:
5.03 m
Explanation:
The wavelength of a wave is given by

where
v is the speed of the wave
f is the frequency of the wave
For the sonar signal in this problem,


Substituting into the equation, we find the wavelength:

Answer:
Average speed of car will be 48 km/hr
Explanation:
Let the total distance is 2d
It is given that first half of the distance car travels with a speed of 40 km/hr
So time taken to cover half of the distance 
Second half of the distance is covered with a 60 km/hr
So time taken to cover second half of the distance 
So total time to cover 2d distance 
Average speed is the ratio of total distance to total time
So average speed 
So average speed of car will be 48 km/hr
As much as 90% of the matter in the universe my be unseen i.e. dark matter. There is a variety of explanations offered by many astronomers and physicists for this dark matter. It could merely be ordinary material such as ultra-faint stars, cold gas, large or small black holes or dust scattered around the universe, all of which emit or reflect too little radiation for our instruments to detect. It could also consist of exotic, unfamiliar particles that we have not figured out how to observe.
The correct options are:
1 How tall are you?
2How far is it from your house to your school?
3How wide is your refrigerator?
All these measurements involve to measure a length. Instead, the other two options involve to measure different physical quantities; for instance, the question
4 How much does your sister weigh?
Involve to measure a weight (and so, a mass), while the question
5 How warm is it in San Diego?
requires to measure a temperature.