Answer:
The initial velocity is 38.46 m/s.
Explanation:
The horizontal distance travel by the tennis ball = 13 m  
The height at which the tennis ball dropped = 56 cm
Now calculate the initial speed of tennis ball.
The vertical velocity is zero.
Below is the calculation. Here, first convert centimetre into kilometre. So, height at which ball dropped is 0.56 km.




 
        
             
        
        
        
Answer:
B
Explanation:
Fermium is a synthetic element with the symbol Fm and atomic number 100. It is an actinide and the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities, although pure fermium metal has not yet been prepared.[3] A total of 19 isotopes are known, with 257Fm being the longest-lived with a half-life of 100.5 days.
It was discovered in the debris of the first hydrogen bomb explosion in 1952, and named after Enrico Fermi, one of the pioneers of nuclear physics. Its chemistry is typical for the late actinides, with a preponderance of the +3 oxidation state but also an accessible +2 oxidation state. Owing to the small amounts of produced fermium and all of its isotopes having relatively short half-lives, there are currently no uses for it outside basic scientific research.
 
        
                    
             
        
        
        
Answer:
The line charge density is 
Explanation:
Given that,
Diameter = 2.54 cm
Distance = 19.6 m
Potential difference = 115 kV
We need to calculate the line charge density
Using formula of potential difference



Where, r = radius
V = potential difference
Put the value into the formula


Hence, The line charge density is 
 
        
             
        
        
        
Answer:
0.00016 kg
Explanation:  
Given: 
Power = P = 1.2 × 10⁹ Watts
Power =  work done / Time 
efficiency = 0.30
Input power = 1.2 × 10⁹ / 0.30 =  4  × 10⁹ W
Energy =  4  × 10⁹ x 60 x 60 = 1.44 x 10¹³ joules 
E = m c² , where c is the speed of light and m is the mass.
⇒ mass = m = E / c²  = (1.44 x 10¹³) / (3 × 10⁸ )² 
                                    = 0.00016 kg