In order to build a hypothesis, Joan should take an educated guess at what the effect of adding salt to the water will be on the water's boiling point. For example, the hypothesis may be,"The boiling point will increase". This hypothesis is one that can be verified or rejected via experimentation. The next step for Joan would be to set up an experiment to test this hypothesis.
Answer: the waves probably hits an open cavity
Explanation:
Sound waves transfers energy in form of vibration through water,the speed of sound is greatest in solids followed by liquids and gases,for we to observe such a reduction from 4000m/s to 1500m/s that means it sound had been transmitted through air like open cavity seen in intrusive rock beneath the earth.
Answer: A.). Be equal to the time the ball hits the group
Explanation:
Complete Question
The complete question is shown on the first uploaded image
Answer:
The value is 
Explanation:
From the question we are told that
The mass of the wheel is m = 6.9 kg
The radius is 
The radius of gyration is 
The angle is 
The force which the massless bar is subjected to 
Generally given that the wheels rolls without slipping on the flat stationary ground surface, it implies that point A is the center of rotation.
Generally the moment of inertia about A is mathematically represented as

Here
is the moment of inertia about G with respect to the radius of gyration which is mathematically represented as

=>
=>
=>
Generally the torque experienced by the wheel is mathematically represented as

=> 
=> 
Generally this torque is also mathematically represented as

=> 
=> 