Answer:
The speed of the baseball is approximately 19.855 m/s
Explanation:
From the question, we have;
The frequency of the microwave beam emitted by the speed gun, f = 2.41 × 10¹⁰ Hz
The change in the frequency of the returning wave, Δf = +3190 Hz higher
The Doppler shift for the microwave frequency emitted by the speed gun which is then reflected back to the gun by the moving baseball is given by 2 shifts as follows;
  

Where;
Δf = The change in frequency observed, known as the beat frequency = 3190 Hz 
 = The speed of the baseball
 = The speed of the baseball
c = The speed of light = 3.0 × 10⁸ m/s
f = The frequency of the microwave beam = 2.41 × 10¹⁰ Hz
By plugging in the values, we have;


The speed of the baseball,  ≈ 19.855 m/s
 ≈ 19.855 m/s
 
        
             
        
        
        
By the right hand rule the magnetic force on the charge acts up 
 
        
                    
             
        
        
        
Answer: Power is 200 W
Explanation: Power P = work done / time used.
P = W/t = mgh/t = 154 kg · 9.81 m/s²· 4 m / 30 s = 201 W
 
        
             
        
        
        
Explanation:
Continental rifts and mid-ocean ridges are both features of a divergent plate margin. 
In both cases plates are moving away from one another. Therefore they are creating new land masses. 
- A continental drift like the east African rift valley is where a continent begins to pull apart or diverges. 
- A mid-ocean ridge is divergent margin in the ocean. 
They are different in that, continental rift occurs within the continental plate that are on land. 
But: 
  Mid-ocean ridges are in the oceanic crust in the ocean . They form the largest physiographic structure on the earth surface called the mid-ocean ridge. 
learn more: 
Descending lithosphere brainly.com/question/9582362
#learnwithBrainly
 
        
                    
             
        
        
        
Explanation:
1. Phases of Venus: Galileo was the first astronomer to use a telescope to observe the celestial objects. Through a telescope he observed that Venus shows the phases just like the Moon. This proved the Heliocentric theory correct against the then prevalent Geocentric theory.
2. Law of Falling bodies: The acceleration due to gravity is independent of weight of the objects that means two bodies of different mass will hit the ground at the same time if dropped from the same height.
3. The uneven surface of the Moon: He observed that the surface of the Moon is uneven and rough.
4. Discovery of the 4 Moons of Jupiter